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Coyotes-Wolves-Cougars.blogspot.com

Grizzly bears, black bears, wolves, coyotes, cougars/ mountain lions,bobcats, wolverines, lynx, foxes, fishers and martens are the suite of carnivores that originally inhabited North America after the Pleistocene extinctions. This site invites research, commentary, point/counterpoint on that suite of native animals (predator and prey) that inhabited The Americas circa 1500-at the initial point of European exploration and subsequent colonization. Landscape ecology, journal accounts of explorers and frontiersmen, genetic evaluations of museum animals, peer reviewed 20th and 21st century research on various aspects of our "Wild America" as well as subjective commentary from expert and layman alike. All of the above being revealed and discussed with the underlying goal of one day seeing our Continent rewilded.....Where big enough swaths of open space exist with connective corridors to other large forest, meadow, mountain, valley, prairie, desert and chaparral wildlands.....Thereby enabling all of our historic fauna, including man, to live in a sustainable and healthy environment. - Blogger Rick

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Sunday, September 30, 2018

In the lower 48 states, there are believed to be only some 300 wolverines in existance spread thinly across the North Cascades of Washington, the Sierra Nevada in northern California, Oregon, Idaho, Montana,, southern Rockies of Colorado and perhaps Utah and Nevada..........."Published accounts by early naturalists indicate that wolverines were rarely, if ever, encountered in the upper Midwest and Northeast regions of the contiguous United States"........... "While historical records are sparse and haphazard in those regions and the habitat conditions today are far differint from the Intermountain West, it should be noted that during the Little Ice Age, AD1300-1870, temperatures in Eastern North America were some 3.6 degrees colder than today, with snowfall occuring as late as June"..........."As an example, in New England and the Mid Atlantic states, the year 1816 was known as 'the Year Without a Summer', with six inches of snow falling in June, with every month of that year recording a hard frost"............"Temperatures dropped to as low as 40 degrees in July and August".........."Knowing this, it is easier to believe that the early settlement records mentioning the Wolverine to be potentially valid".................."Regionally referred to as the mountain devil, the quickhatch, the carcajou and the skunk bear, the Wolverine is our largest Weasel, topping off at 40 pounds"............."Perhaps North Americas most ferocious carnivore, a single Wolverine can claw and gnash down an elk and fight off wolves and bears over any size animal carcass" .............."But for all their ability to defend themselves and seek out food, their habitat requirement of high altitude boreal forests and/or alpine tundra coupled with late, deep Spring snowpack, make them highly vulnerable to extirpation in our human dominated world"................."A solitary animal, one male may mark off a territory up to 600-square miles (half the size of Rhode Island), breeding with several females in its range"............ "Two year old females are capable of breeding only once annually,(perhaps 53% of female Wolverines actually breed each year) raising their 1-2 kits in the Spring, in the heavy snowpack, sometimes no lower than 8,000 feet high in the mountain peaks"........."Like the Lynx, Wolverines have wide flat snowshoe-like feet, with their fur being frost resistant".............."The Mountain Men Trappers of Rocky Mountain North America during 1800-1840 seriously hunted them, turning their fur into winter resistant coats".............."Overhunting, coupled with habitat alteration and lack of Spring snowpack, along with their previously mentioned low-end birthrate has made them a fragmented and isolated animal, one with a small population poorly adapted to survive in today’s ever-anthropocentric world where smaller and smaller American locales experience deep Spring snowpack for optimum breeding"..........The U.S Fish and Wildlife Service which has previously refused to put the Wolverine on the Endangered Species List has been ordered by a Federal Judge to re-evaluate that decision-perhaps keeping the Wolverine with us for sometime longer.................Truly teriffic to actually see an unusally large litter(3 kits) of Wolverines documented this past July in the Bitteroot Mountains of Montana(see video in article below)............We hope beyond hope that this charismatic and truly American fellow denizen somehow gets the protection it deserves, so as to "to live long and prosper"

https://www.wideopenspaces.com/wolverine-babies-spotted-for-the-first-time-ever-in-the-bitterroot-national-forest/

WOLVERINE BABIES SPOTTED FOR THE FIRST TIME EVER IN THE BITTERROOT NATIONAL FOREST











Posted by Brad Smith

So, this is kind of a big deal. 

Wolverines are fierce little predators. They make bears look elsewhere if there’s an animal carcass up for grabs. Even though these animals are widespread, there aren’t many in the lower 48 states.
The highest density the United States has is in Alaska. Otherwise, they inhabit almost all of northern Canada as well as parts of Europe.
That said, video evidence has just emerged that spotted wolverine babies and their mother in the Bitterroot National Forest of Montana













Every now and then, we get reports of single, nomadic wolverines crossing the northern parts of the U.S. However, this indicates we might be getting a breading population in some areas.






“We?re beyond excited to have this great footage of wolverine babies in the Sapphire Mountains of the Bitterroot National Forest,” said Kylie Paul, a coordinator of scientists and citizens working together to track these creatures. “There are only small pockets of high-quality wolverine habitat in the Sapphires and this shows how valuable those secure pockets are for these critters.”
Since the inception of the program back in 2015, only 10 wolverines have been spotted in this area. It seems like there’s going to be a boom of more footage and sightings soon.
CLICK ON ARROW BELOW TO VIEW THE BITTEROOT WOLVERINE KITS FROM THIS SUMMER 2018


Friday, September 28, 2018

Feral Cats are not good rat killers............"At an industrial waste recycling site in Brooklyn, a south-eastern borough of NYC, researchers documented the direct and indirect influences of feral cats on a partially-identified population of city rats"............... "This partly-enclosed urban ecosystem was under heavy pressure from cats, as evidenced by the number of cats present there"........... "Of the 259 instances of behavior recorded by cats over 79 days/nights, only 3 times did a cat pursue a rat—and only once across an open floor"................"Completely surprising that an area where up to three cats patrolled within the same 24-h period, would have so few direct predation attempts". ............."Important to note in evaluating the cat predation potential on Rats is the fact that when sufficient food is available, one pregnant female rat can give birth to 6-10 litters of 12 pups each year"............. "In areas where less food is available(rats reproducing less frequently), it is possible that the direct effects of predation by cats could be more significant, but this has not been verified thus far"...............What is determined is that Cats exert the "LANDSCAPE OF FEAR" PARADIGM on rats, causing the rats to avoid cats by changing their behaviour............"But without any significant kill ratio impacted on the rats, the benefits of releasing cats for their alleged ability to kill rats is far outweighed by the documented predation cats exert on native wildlife"


https://phys.org/news/2018-09-cats-rats.html


In the battle of cats vs. rats, the rats are winning

September 27, 2018, Frontiers




The first study to document interactions between feral cats and a wild rat colony finds that contrary to popular opinion, cats are not good predators of rats.


 Coat patterns of five feral cats and subsequent ethogram used to score their behaviors at a semi-enclosed industrial building in New York City from Dec. 27, 2017—May 28, 2018. Cat behaviors scored (modified from Stanton et al., 2015) include walking: forward locomotion where animal moves slowly. Running : animal uses forward locomotion at a rapid gait. Stalking: slow forward motion in crouched position, with head low and eyes focused on potential prey. Predation : hunting or killing that leads to a direct kill. Sniffing: cat smells floor or object by inhaling air through the nose. Feeding: animal ingests food, usually from floor. Sitting: animal is immobile in upright position. Marking: while standing with tail raised vertically, cat releases jet of urine backwards onto a substrate of an object. Tail may quiver as urine is released.












 In a novel approach, researchers monitored the behavior and movement of microchipped rats in the presence of cats living in the same area. They show the rats actively avoided the cats, and only recorded two rat kills in 79 days. Published as part of a special "rodent issue" in Frontiers in Ecology and Evolution, the findings add to growing evidence that any benefit of using cats to control city rats is outweighed by the threat they pose to birds and other urban wildlife.



"Like any prey,  overestimate the risks of predation. In the presence of cats, they adjust their behavior to make themselves less apparent and spend more time in burrows," says the study's lead researcher Dr. Michael H. Parsons, a visiting scholar at Fordham University. "This raises questions about whether releasing cats in the city to control rats is worth the risks cats pose to wildlife."

while cats can kill rats, ita appears that
it does not happen that often




People have long associated cats as the natural enemy of rats. However Australian and US researchers say cats prefer smaller, defenseless prey such as birds and smaller native wildlife—which makes cats a threat to urban ecosystems.
"New Yorkers often boast their rats 'aren't afraid of anything' and are the 'size of a cat'," says Parsons. "Yet cats are commonly released to control this relatively large, defensive and potentially dangerous prey."
"Until now, no one has provided good data on the number of city rats killed by cats," adds co-author Michael A. Deutsch, from Arrow Exterminating Company Inc. "But the data have been very clear as to the effect of cats on native wildlife."
When  invaded a New York City waste recycling center, the researchers took the opportunity to correct the record. Their team was already studying a colony of more than 100 rats living inside the center, by microchipping and releasing the animals to study their life history. When the cats entered the research area, they set up motion-capture video cameras to quantify the effect of the cats on the rats—the first time this has been studied in a natural setting.

Too bad that this occurs so infrequently




"We wanted to know whether the number of cats present would influence the number of rats observed, and vice versa," says Parsons. "We were also interested whether the presence of cats had any effect on eight common rat behaviors or their direction of movement."
The researchers examined 306 videos taken over 79 days. Although up to three cats were active beside the rat colony each day, only 20 stalking events, three kill attempts and two successful kills were recorded in this time. Both kills took place when cats found rats in hiding; the third attempt was an open-floor chase where the cat lost interest.
The videos also revealed that in the presence of cats, the rats spent less time in the open and more time moving to shelter.
"The presence of cats resulted in fewer rat sightings on the same or following day, while the presence of humans did not affect rat sightings," says Parsons. In contrast, the number of rats seen on a given day did not predict the number of cats seen on the following day.
"We already knew the average weight of the rats was 330 g, much more than a typical 15 g bird or 30 g mouse," says Parsons. "As such, we expected a low predation rate on the rats—and our study confirmed this."
"We are not saying that cats will not predate city rats, only that conditions must be right for it to happen," adds Deutsch. "The cat must be hungry, have no alternative less-risky food source, and usually needs the element of surprise."
The findings could explain why people continue to release cats as "natural" rat control tools. "People see fewer rats and assume it's because the cats have killed them—whereas it's actually due to the rats changing their behavior," says Parsons.
"The results of our study suggest the benefits of releasing cats are far outweighed by the risks to wildlife," he adds.
The research team plans to continue collecting data as part of their long-term study and will update their findings as new information becomes available.
"Much more research is needed to better understand the city rat problem, we hope our successes will compel others to perform similar studies in other venues," says Parsons.
But for now, in the battle of New York City  and rats it appears the rats are winning.
More information: Frontiers in Ecology and EvolutionDOI: 10.3389/fevo.2018.00146 , https://www.frontiersin.org/articles/10.3389/fevo.2018.00146/full

Monday, September 24, 2018

The long held theory that Woodpecker brains are immune to damage from the constant pounding they initiate on trees has recently been called into question..............."In fact scientists now say that.they do experience a type of protein accumulation that is associated with trauma and brain damage in humans"........."However, it's unclear if the presence of this protein, known as "tau," points to brain damage in the birds"..........."In fact, tau might even serve as a protective adaptation, providing a buffer around the birds' neurons that insulates them against harm, according to the study".........."This new insight into woodpecker brains could inspire researchers to take a closer look at the proteins that have been linked to brain damage in people"................"A woodpecker hammering away at a tree experiences forces up to 1,400 times that of Earth's gravity, or 1,400 G's"..............."To put that into perspective, humans can withstand about 8 G's of continuous momentum before eventually blacking out, and a sudden application of 50 G's would detach most of our organs"............."Even relatively small amounts of g-force in people can cause concussion"..........."How do woodpeckers prevent this type of injury?"................"They have a number of special physical features, such as skulls with spongy layers — particularly in the front regions — that cushion their brains"............"Robust neck muscles also help to soften the impact, while thick inner eyelids protect their eyes"



http://www.livescience.com/61661-woodpeckers-brain-damage.html

Does All That

 Headbanging Leave a Mark on Woodpeckers' Brains?








Scientists may have just pecked new holes in the widely held idea that woodpeckers' brains suffer no ill effects from the considerable force generated by their high-speed pecking.
A new study — the first to examine the birds' brains — shows that woodpecker brains are not immune to these repeated impacts, and that they experience a type of protein accumulation that is associated with trauma and brain damage in humans.
However, it's unclear if the presence of this protein, known as "tau," points to brain damage in the birds. In fact, tau might even serve as a protective adaptation, providing a buffer around the birds' neurons that insulates them against harm, according to the study. This new insight into woodpecker brains could inspire researchers to take a closer look at the proteins that have been linked to brain damage in people, the study authors told Live Science. [5 Ways Science Could Make Football Safer]
A woodpecker hammering away at a tree experiences forces up to 1,400 times that of Earth's gravity, or 1,400 G's. To put that into perspective, humans can withstand about 8 G's of continuous momentum before eventually blacking out, and a sudden application of 50 G's would detach most of our organs. Even relatively small amounts of g-force in people can cause concussion, lingering pain in the neck and back, and red dots on the skin from ruptured capillaries — known as "G-measles" or "geasles" — according to Go Flight Medicine, a website for aviation and medical professionals.                                     
How do woodpeckers do it? They have a number of special physical features, such as skulls with spongy layers — particularly in the front regions — that cushion their brains. Robust neck muscles also help to soften the impact, while thick inner eyelids protect their eyes
For generations, scientists accepted that woodpeckers didn't develop abnormalities in their brains from the repeated impacts. Then again, no one had ever checked woodpecker brains for signs of damage, the study authors noted. As the woodpecker lineage has been around for about 25 million years, it was widely thought that the birds couldn't possibly have any serious brain issues, study co-author Dr. Peter Cummings, an assistant professor of anatomy and neurobiology at the Boston University School of Medicine, told Live Science.

Specimens from The Field Museum provided researchers with samples of woodpeckers' brain tissue.    Credit: The Field Museum








But in the new study, the researchers looked for evidence where no one else had before: in the tissues of woodpeckers' brains. To do that, study lead author George Farah, then a graduate student at the Boston University School of Medicine, had to figure out how to remove the organ in one piece. "It took some trial and error," he told Live Science.
Unlike the human skulls that Farah had previously dissected, woodpeckers' skulls have a bony plate protecting their optic region, which is located by the brain stem and is quite large, he said. Farah used a Dremel tool and very fine scalpels, cutting far lower in the back of the skull than he would have in a human, to accommodate removal of the optic region and part of the brain stem along with the other portions of the brain, Farah said.
He then stained the tissue to reveal tau proteins, which showed up in the woodpeckers' brains but not in the brains of other types of nonpecking birds in the experiments' control group, Cummings said. [Inside the Brain: A Photo Journey Through Time]

A great spotted Woodpecker (Dendrocopos major) on a tree.
Credit: Dietiked | Dreamst






Tau proteins stabilize neurons, and they can appear in human brains for a number of reasons, including injury, neurodegenerative disease and normal aging processes, Cummings noted. Tau itself isn't necessarily a problem, but the buildup of tau proteins in humans can interfere with neuron function and is associated with the brain disease known as chronic traumatic encephalopathy, or CTE. CTE can lead to symptoms such as depression, memory loss and difficulties in cognition and motor abilities, and the disease tends to worsen with time, Live Science previously reported.
The presence of tau proteins in woodpecker brains shows that their brains are not invulnerable to the effects of forceful pecking. Nevertheless, the tau proteins aren't necessarily hinting that woodpeckers suffer from pecking-related neurodegenerative disease or brain damage, the scientists wrote in the study.
"Something — tau — was there that shouldn't necessarily be. But whether it's a good thing or a bad thing, we don't know," Farah said.
"I wonder if what we're seeing in the woodpeckers may be a protective mechanism for the neurons," Cummings added. "You have skull modifications, tongue modifications —why would that stop at the brain? Why would the brain not participate in that process of evolutionary adaptation, and molecularly do that by the expression of a protective protein that may help stabilize neurons during that pecking procedure?"
The next step is to figure out what kind of tau proteins are involved in this protective mechanism and what other proteins are linked to them, the researchers said.
The findings were published online Feb. 2 in the journal PLOS ONE.

Sunday, September 23, 2018

"Fisher (Pekania pennanti) and American marten (Martes americana) are mustelids that are sensitive to forest management and therefore considered to be ecological indicators of forest health"...................."Fisher populations have increased in eastern North America since the early 2000s and this could have resulted in a northeastern extension of the species’ range and increased overlap with marten’s range"..............."Trappers highlighted the lack of exclusivity of marten and fisher to coniferous forests, although marten is more closely associated with them than is fisher"....................."Fisher apparently also takes advantage of open environments, including agroforestry systems"........................"Moreover, climate change increases the frequency of freeze-thaw events that cause the formation of an ice crust on the snow surface, which favors fisher movements"............"The fisher is very opportunistic and eats whatever it encounters"................"It is a known predator of the North American porcupine (Erethizon dorsatum), but this species is not its main food source".................."Like the marten, the fisher hunts hare, squirrels, gallinaceous birds, small mammals, and small birds"..................."Because of its size and strength, the fisher can access a greater diversity of prey than can marten, including (semi-)aquatic animals (fish, beaver, muskrat [Ondatra zibethicus], mink [Neovison vison]) and larger-sized terrestrial animals, such as woodchucks (Marmota monax), striped skunk (Mephitis mephitis), farm chickens (Gallus gallus domesticus), domestic cats (Felis silvestris catus), and even red fox (Vulpes vulpes)"......................."Fishers also feed upon moose carcasses or animals caught in traps, including martens"..............."The fisher also eats live martens and is one of the latter’s principal predators"..............."The fisher was identified as a competitor and even a predator of the marten""


More fishers and fewer martens due to cumulative effects of forest management and climate change as evidenced from local knowledge

Journal of Ethnobiology and Ethnomedicine201713:51

ABSTRACT

Background

Monitoring of fur-bearing species populations is relatively rare due to their low densities. In addition to catch data, trappers’ experience provides information on the ecology and status of the harvested species. Fisher (Pekania pennanti) and American marten (Martes americana) are mustelids that are sensitive to forest management and therefore considered to be ecological indicators of forest health.


 The American Marten(top) and the Eastern Fisher(bottom)




















The Abitibi-Témiscamingue region of western Quebec (Canada),(blue shaded),(Full Quebec Province in brown) at the northern limit of the overlapping ranges of the two mustelid species.





Fisher populations have increased in eastern North America since the early 2000s and this could have resulted in a northeastern extension of the species’ range and increased overlap with marten’s range. 

North American Range Maps for a) Martes americana, American Marten; b) M. pennanti , Fisher; c) Mephitis mephitis , Striped Skunk. Marten map from Chermundy 2010a, fisher map from Chermundy 2010b, Striped skunk map from Schröter 2010. Distribution data are from IUCN Red List. 











Moreover, habitats of both species are subject to natural and anthropogenic disturbances. The objective of this study was to document the knowledge held by local trappers in the northern area of sympatry between fisher and marten to identify factors that could explain variation in populations of the two species and interactions between them.


2013 Locations of American marten ( Martes americana ; n = 29) and fisher ( M. pennanti ; n = 34) sampling sites. Inset shows location of Ontario and Quebec, Canada, and New York, USA, within central North America. doi:10.1371/journal.pone.0056204.g001










Method
Forty-one semi-directed interviews with Indigenous and non-Indigenous trappers in the Abitibi-Témiscamingue region of western Quebec (Canada), at the northern limit of the overlapping ranges of the two mustelid species.

Results

Trappers highlighted the lack of exclusivity of marten and fisher to coniferous forests, although marten is more closely associated with them than is fisher. Fisher apparently also takes advantage of open environments, including agroforestry systems. Moreover, climate change increases the frequency of freeze-thaw events that cause the formation of an ice crust on the snow surface, which favors fisher movements.

The American Marten(top) and the Eastern Fisher(bottom)

















Predator-prey relationships

Marten prey species

According to the participants, the marten feeds primarily on squirrels and other small mammals. The term “mouse” was used generically to refer to several small mammals, including voles, shrews and other unspecified species. Squirrels included several species of Sciuridae, such as the red squirrel (Tamiasciurus hudsonicus), the large flying squirrel (Glaucomys sabrinus) and the striped chipmunk (Tamias striatus). Marten also hunt snowshoe hare (Lepus americanus) and gallinaceous birds, including ruffed grouse (Bonasa umbellus) and spruce grouse (Falcipennis canadensis), especially in winter. Ruffed grouse catches were attributed to hunting under the snow, but the marten also consumes the eggs and preys upon the young of this species. Further, participants felt that the marten’s ability to climb trees also allowed it to feed upon small perching birds. Other dietary components that were cited by participants included carcasses of moose (Alces americanus) and beaver (Castor canadensis), animals that had been caught in traps, and red raspberries (Rubus idaeus L.).
[The marten, she eats a lot of mice. A year where you have a lot of mice – and this is a 3-year mouse cycle – the marten will raise four young, (…) but the following year you will have practically no babies. The squirrel is also a feast for the marten: when you have the marten, you do not hear squirrel calls.] [E1-Z2]
[People think that the marten catches hares, partridge, but it is mostly the mouse that it hunts. When there is too much snow, she switches to the air (in the trees) to catch squirrels, flying squirrels.] [AT12-Z2]

Fisher prey species

Participants have pointed out that the fisher is very opportunistic and eats whatever it encounters. It is a known predator of the North American porcupine (Erethizon dorsatum), but this species is not its main food source. Like the marten, the fisher hunts hare, squirrels, gallinaceous birds, small mammals, and small birds. Because of its size and strength, the fisher can access a greater diversity of prey than can marten, including (semi-)aquatic animals (fish, beaver, muskrat [Ondatra zibethicus], mink [Neovison vison]) and larger-sized terrestrial animals, such as woodchucks (Marmota monax), striped skunk (Mephitis mephitis), farm chickens (Gallus gallus domesticus), domestic cats (Felis silvestris catus), and even red fox (Vulpes vulpes). Fishers also feed upon moose carcasses or animals caught in traps, including martens. Most participants also pointed out that the fisher also eats live martens and is one of the latter’s principal predators. Like the marten, the fisher also eats berries.
[(The fisher) even eats fish, it goes up to whitefish spawning grounds, where it often drags fish ashore, like the lynx. The marten she does not do that, she is not able to kill a fish in the water.] [Ex30-Z3]Conclusion

CONCLUSION
The fisher was identified as a competitor and even a predator of the marten. Furthermore, the fisher is less affected than the marten by forest management, and it also seems to benefit from climate change to a greater extent.

Saturday, September 22, 2018

When you hear the word LEECH, I imagine that the image of a "blood-sucker" fills your brain with fear and disgust................."Interesting enough of the 600 Leech species worldwide only 10% actually suck blood"..........."The rest get their nourishment primarily from eating larvae, invertebrates and decaying matter"..............."And even if you(or another mammal, fish or amphibian) get bitten by one, the victim likely will not feel it due to their three to four rows of teeth that make a very even slice when cutting into skin"........."Leech saliva also contains both anticoagulant and anesthetic agents, so not only will you(or any other meal source) be unlikely to feel the leech bite, the blood will flow more freely into the leech".............. "A meal typically lasts from half an hour to a few hours, during which time a leech will swell to several times its pre-meal size".............."Once satiated, a leech will simply remove itself from its host"............. "It may not need another meal for several months"............."When they’re not hungry – or looking for a mate – leeches tend to stay hidden beneath rocks, logs, and other debris in the water"..............."During winter, they survive by burrowing into mud below the frostline"..............."Leeches provide food for fish, turtles, and waterfowl"............"While the medicinal use of leeches, which stretches back thousands of years, was often dubious, a modern version of the practice has been making a comeback in recent years"..............“Leeches are most commonly used with tissues that are likely to go necrotic after time for example, on skin transplants or in reconstructive surgery"................"Basically, the leech’s combination of anticoagulants and suction helps restore healthy blood flow to the affected area"...............“It’s pulling fresh blood through the tissue that might die otherwise"


Leeches: They Don’t All Suck Blood


1046
Leeches: They Don’t All Suck Blood
Illustration by Adelaide Tyrol
Most folks who’ve enjoyed a dip in the local swimming hole – whether at a pond, lake, or river – have probably found, on occasion, a leech or two stuck to their skin while toweling off afterwards. Although some might think these slimy little suckers are gross, they mean – and do – no harm. They’re just hungry.
“With some 600 species, there’s a surprising amount of diversity,” said Adam Weaver, a biology professor at Vermont’s Saint Michael’s College. And the majority of leeches aren’t even bloodsuckers.
Weaver said scientists estimate about 10 percent of leech species – which are found from the tropics to desert watering holes to Antarctica – are parasitic, and only a couple of the 70 or so freshwater species found in North America are bloodsuckers. The rest get their nourishment primarily from eating larvae, invertebrates, and decaying matter.










That’s likely small comfort for the squeamish swimmer sporting a slimy worm. Chances are, though, if you’ve ever had a leech attached to your body, you likely didn’t even notice it until you saw it, because you never felt the bite.
“Leeches tend to have three to four rows of teeth that slice into the skin, making this very even slice,” said Weaver.
Their saliva also contains both anticoagulant and anesthetic agents, so not only will the meal source be unlikely to feel the leech bite, the blood will flow more freely into the leech. A meal typically lasts from half an hour to a few hours, during which time a leech will swell to several times its pre-meal size. Once satiated, a leech will simply remove itself from its host. It may not need another meal for several months.
Leeches of the bloodsucking variety don’t just like humans, of course; they’ll also feed on other mammals, as well as on fish and amphibians. They attach with both anterior and posterior suckers. The latter is mainly for adhesive purposes; the bloodsucking happens through the anterior sucker, which contains the leech’s teeth.













These segmented worms are sensitive to changes in movement and light, so a swimmer splashing through the water may attract a hungry leech’s attention. When they’re not hungry – or looking for a mate – leeches tend to stay hidden beneath rocks, logs, and other debris in the water. During winter, they survive by burrowing into mud below the frostline.
After emerging in the spring and consuming their first meal of the year, a leech’s next priority is mating. Although hermaphroditic, they reproduce sexually, with both leeches exchanging sperm. They deposit eggs in a cocoon, which they then typically attach to a rock or log underwater until the baby leeches emerge. The timing here depends on the species of leech.
One of the bloodsucking leech species common in our region is Macrobdella decora, also known as the North American medicinal leech, although the European species Hirudo medicinalis and Hirudo verbanahave been used more commonly for medicinal purposes.
While the medicinal use of leeches, which stretches back thousands of years, was often dubious, a modern version of the practice has been making a comeback in recent years.
“Leeches are most commonly used with tissues that are likely to go necrotic after time,” Weaver said – for example, on skin transplants or in reconstructive surgery. Basically, the leech’s combination of anticoagulants and suction helps restore healthy blood flow to the affected area: “It’s pulling fresh blood through the tissue that might die otherwise.”
While pharmaceutical anticoagulants tend to be strong and can cause bleed-outs in remote parts of the body, leeches, Weaver said, target the specific area that needs treatment.
All of this may seem irrelevant for the swimmer who jumps into the water for refreshment and comes up with a leech – or several – attached. If leeches make you squirm, just be glad to live here, where leeches typically measure only an inch or two and are confined to shallow water.
Some species in the tropics aggressively attack blood meals, Weaver said, and can travel “several lengths outside of the water.” And the giant Amazon leech, a bloodsucking species found in South America, can grow up to 18 inches long.
Here, leeches are harmless, if not always welcome by human bathers. They provide food for fish, turtles, and waterfowl and can serve as bait for fishermen. An attached leech can usually be removed easily by sliding a fingernail under its anterior mouthpart. And if you really want to avoid the little suckers, stick to deep water.
Meghan McCarthy McPhaul is an author and freelance writer.