Cats And Coyotes Divvy Up The Chicago Suburbs

coyoteI’ve been to Chicago and the surrounding area plenty of times, but I never thought to look for coyotes. I hadn’t realized that the animals have been expanding their territory over the last several hundred years, and they can now be found in many U.S. and Canadian cities, including Chicago. In many of these areas, coyotes are now the largest carnivores, at the top of the food web. And that might be affecting some of the animals we are more familiar with.

Urban coyotes have a varied diet, consisting mostly of small rodents, white-tailed deer, fruit (carnivores aren’t strictly meat eaters), bunnies and birds. They also eat a small number of cats, which led a group of scientists who are studying urban coyotes in the Chicago area to look into how coyotes and feral cats interact in the city’s suburbs. The results of their study appear in PLOS ONE.

feralcatBetween February 2008 and September 2009, the researchers captured 43 cats in eight sites in the suburbs west of Chicago. They then took blood samples from the cats and fitted 39 with radiocollars (two cats were thought to be pets, one was too small for the collar, and one was so sick it was euthanized). Getting good data from the cats was difficult: A fifth of the cats died during the study period, a quarter were adopted, 13 percent had collars that didn’t last until the end of the study, 10 percent were never heard from again, and, in what is the most mysterious statement in the study, 23 percent “were removed from the system by cat advocates opposed to our research.” Despite the difficulties, however, the researchers were able to get good tracking data for a number of kitties, enough to map out several cats’ home ranges and plot them against the ranges of coyotes in the urban coyote project.

The cats and coyotes, the researchers found, did overlap a bit in their travels, but for the most part, cats stuck to areas around homes and buildings. The coyotes, in contrast, preferred natural habitats away from human development. “Coyotes in our system appear to inhibit cat use of the natural habitat fragments through a combination of predation and cat avoidance of coyote activity,” the researchers conclude. “It is clear the two species are largely separated across the metropolitan area.”

This is only a small study, but the team speculates that coyotes may be controlling the feral cat population throughout the Chicago area, keeping the cats out of the fragments of natural habitat that dot the suburbs. If the pattern holds in other areas, then in regions where coyotes can be found, the ecological impacts of cats (that is, the cats’ killing of birds and other native wildlife) might be overestimated. Cats have gained a reputation for being evil murderers that devastate wildlife, but we’re finding that the story is far more complicated. And its one that needs to be better elucidated.

Images courtesy of flickr users John Picken (Chicago coyote, top) and cats marcoff (Chicago feral cat, bottom)

Sea Otters Again Prove Their Worth

seaotterIf you take a class in ecology, sea otters inevitably come up. They’re a classic example of a keystone species — that is, an animal or plant or other organism that has a critical role in the ecosystem such that, if you take it out of the system, everything collapses. Sea otters are a keystone species in the kelp forests off California. If the sea otters aren’t around to munch on sea urchins and keep the urchin population in check, urchins proliferate and graze the kelp to death. Without the kelp, other animals that depend on the vegetation — including crabs and geese — suffer. All that happens because there are no sea otters.

Now a group of scientists from California have found that sea otters play a similar keystone role in another coastal California ecosystem — the seagrass beds of Elkhorn Slough. The study was published this week in PNAS.

Elkhorn Slough is an estuary near rich fields of strawberries and artichokes. Those farm fields are a problem because when water drains off them into the estuary, it carries nutrients (from fertilizer) and pesticides. Nutrient loading is a particular problem in marine ecosystems as it changes the abundance of certain organisms and sets everything out of whack in the food web. Some critters thrive, but many suffer. And in Elkhorn Slough, seagrass beds have been on the decline.

Scientists suspected, however, that sea otters may play an important role in this area. When the researchers looked at a 50-year record of nutrient levels, seagrass and sea otters, they noticed a pattern. There were no sea otters in the area between 1965 and 1984. During that time, when nutrient levels started to increase, the seagrass beds declined. But when the sea otters were reintroduced to the area, the seagrass beds again thrived, even though the nutrient levels continued to increase.

The researchers suspected that the link between the sea otters and seagrass was not sea urchins, as in the kelp forests, but crabs: The sea otters eat the crabs. Without so many crabs around, grazing herbivore species thrive. Those grazers eat algae that lives on and harms the seagrass, and as a result, the seagrass thrives.

But when there are no otters around, this all falls apart. The crabs outcompete the algae grazers, letting the algae proliferate. And with the nutrients boosting the algae population, the seagrass beds suffer.

“This estuary is part of one of the most polluted systems in the entire world, but you can still get this healthy thriving habitat, and it’s all because of the sea otters,” study author Brent Hughes of the University of California, Santa Cruz, told BBC News. “So it’s almost like these sea otters are fighting the effects of poor water quality.”

This new pattern is a bit more complex than the classic sea otter–kelp story, but it’s yet another example of how important top predators are and the disaster that can follow their removal.

Image courtesy of flickr user Blake Matheson

Secrets Of A Cape Fur Seal Pup’s Coat

sealA Cape fur seal doesn’t become a marine mammal until it is several weeks old, spending that time only on land. Stuck on shore with little shade available, the pups have to endure the hot sun, usually unable to take a quick dunk to cool off as its parents would do because the waters are too dangerous. So how does a pup cool off? It doesn’t have to, say scientists reporting in PLOS ONE. When they’re young, these animals have a special coat that keeps them cool.

The researchers studied six Cape fur seal pups that were born between 2010 and 2012 at Zoo Rostock in Germany. They measured the pups’ surface temperatures with an infrared camera as well as skin temperature and rectal temperature with increasingly invasive techniques (there’s never going to be a good way to get that last one remotely).

As long as a pup’s fur was dry, it was able to maintain a stable internal body temperature. But when a pup got wet — when its mom took it for a quick dunk, or it rained — its hair became flattened and stringy, and the pup’s body temperature dropped. Sometimes they shivered. (Adorable note: The pups would shake themselves like dogs when they came out of the water.)

The researchers conclude that the pup’s fur is adapted to the terrestrial lifestyle that marks these animals’ early lives. The fur traps a layer of air near the skin that insulates against heat and cold. The tradeoff is that this fur doesn’t insulate well in water. This fur coat has to change as the seals age and adapt to the marine life.

The fluffy fur may protect a seal pup against the heat, but it’s made it vulnerable to human predators. The Namibian government lets people kill 80,000 Cape fur seal pups each year; a pelt can be sold for $7.

Image courtesy of flickr user DragonWoman

What’s A Manatee Doing In Virginia?

manateeVirginians are excited this week because a manatee has come to visit. It was spotted this weekend in the Appomattox River (see video below). Manatees are residents of Florida, so what’s this one doing so far up the East Coast? Well, it’s not actually all that far out of its territory if you consider that manatees have swum as far north as Cape Cod. It seems that sometimes Florida’s state marine mammal likes to wander. But why?

Well, no one has ever asked the manatees (or if they have, they never got a good answer), but news reports describing various incidences of manatees in the north have plenty of speculation: The AP report about Virginia’s current visitor, for example, says that manatees sometimes leave Florida when waters there get too warm; they go north to cool off. A 2006 story about a Cape Code manatee says that it’s common for manatees to travel up to the shallow areas off the Carolinas. USGS wildlife biologist Cathy Beck speculated that the manatee followed a warm current up the coast to Massachusetts.

Manatee sightings north of the Carolinas are not uncommon these days. Baltimore has even had a repeat visitor, nicknamed Chessie, that has shown up multiple times since 1994. But whether more manatees are swimming north in the summer or more people are noticing them isn’t known.

But for now wandering manatees are just an interesting oddity, and perhaps a distraction from the bigger problems that the species faces. See, the Florida manatee (a subspecies of Trichechus manatus) is in trouble. The IUCN lists them as endangered and says there are fewer than 2,500 individuals. More than 200 manatees died in a deadly algal bloom earlier this year. They’re victims of habitat loss and often in conflict with the fishing industry (manatees get entangled in fishing gear). Boat collisions are also a huge danger. In 2010, for instance, 83 animals were killed in encounters with boats. One newspaper estimated that this year manatees are dying from all these various causes at a rate of 100 per month.

Some groups in Florida have petitioned to have the manatee’s status upgraded from Endangered to Threatened, noting that aerial surveys of the animals show that the Florida population has increased in recent years. But Caryn Self-Sullivan, a conservation biologist at Nova Southeastern University in Florida, argued in a blog post earlier this year that there’s little reason to change the mammal’s classification. Aerial surveys don’t produce reliable counts; mild winter conditions and poor visibility can skew the results. And changing the manatee’s status to Threatened would still indicate that they were in danger of extinction and in need of protection. “To reduce protection would likely produce a significant and deleterious effect on the manatee population in Florida,” she writes.

Classifying the manatee as Threatened wouldn’t immediately change any of the laws that protect the animals. But this is all moot for now; the reclassification discussion is on hold. That would seem to be good news, except that the hold is in response to this year’s high death rate. Manatees just can’t get a break.

Image courtesy of flickr user NOAA’s National Ocean Service; video from cody_beeler on Instagram

Yellowstone Wolves Good For Grizzlies


The reintroduction of wolves to Yellowstone National Park, starting in 1995, has had some good effects on the food web there: The wolves keep the elk population in check, and with fewer elks to graze on the vegetation, plants including aspen and willows have rebounded. There’s further evidence that this greater availability of plants has been a boon to the beaver and bison populations in the park.

Now comes a study, just published in the Journal of Animal Ecology, that shows that grizzly bears have also gotten a boost to their diet from the wolves’ return.

Yellowstone grizzly bears are a bit different than grizzlies elsewhere — they don’t eat many berries. Studies of the bears that were conducted in the late 20th century found that Yellowstone grizzlies had some of the lowest berry consumption in the interior of North America. That was a bit weird because from July to October, female grizzlies usually gorge on the fleshy fruits. Berry calories can be easily converted to and stored as fat, perfect for bulking up for the long hibernation as well as the pregnancy and birth that usually take place during winter.

“Wild fruit is typically an important part of grizzly bear diet,” William Ripple, an ecologist at Oregon State University and coauthor on the new study, said in a statement. “At certain times of the year [berries] can be more than half their diet in many places in North America.”

Ripple and his colleagues have been studying how the reintroduction of wolves to Yellowstone has affected the Yellowstone food web, and they thought that the berry situation for the Yellowstone grizzlies might have changed with wolves’ return. The issue is more than just a note of academic interest. After the wolf population reached sufficient numbers that the government wasn’t worried they’d die out, the wolves were removed from the endangered species list in 2011, letting hunting of them start up again. If it turns out that the wolves have an impact on other endangered critters, such as grizzly bears, conservationists might have a better case for stopping the hunt.

Since asking grizzly bears to complete a survey of their diet isn’t exactly practical, the researchers analyzed bear poop, comparing scat collected from 2007 to 2009 with data from 1968 to 1987. That latter time was one when elk were increasing in numbers (they went from 3,000 in 1968 to 19,000 in 1994) and bears weren’t doing so well. The bears lost their easy meals in 1971 when the park closed all of its garbage dumps. That led to a lot more bear-human conflicts, and many bears were removed or killed. By 1975 the grizzlies were listed as threatened.

The team found that the percentage of fruit in bear scat declined from 1968 to 1987, as the elk were increasing. But after the wolves had come back into the picture, the bears began eating a lot more berries. In August, for example, the male diet was as much as 29 percent fruit and a female’s up to 39 percent.

What’s happening is that with fewer elk to munch on the park’s vegetation, the berry plants can thrive and bears can eat their fill. It’s likely that other critters, including birds and rodents, are benefiting from the recovering fruit harvest as well, the researchers say.

“Studies like this also point to the need for an ecologically effective number of wolves,” study coauthor Robert Beschta, of Oregon State University, said in a statement. “As we learn more about the cascading effects they have on ecosystems, the issue may be more than having just enough individual wolves so they can survive as a species. In some situations, we may wish to consider the numbers necessary to help control overbrowsing, allow tree and shrub recovery, and restore ecosystem health.”

Photo courtesy of Yellowstone National Park

The Iberian Lynx Is Doomed — Maybe


The world’s most endangered cat is not the lion or cheetah or tiger; it’s the Iberian lynx. Already at risk for a number of reasons I’ll get into below, a new study from Nature Climate Change predicts that the lynx could be extinct by 2060, driven off the planet by anthropogenic climate change.

As its name suggests, the Iberian lynx belongs on the Spanish-Portuguese peninsula, where it exists in a few isolated places in southwestern Spain and perhaps Portugal (though no one really knows). The IUCN estimates the lynx population at a mere 84 to 143 adult cats; recent counts suggest there may be as many as 250 of these kitties. Even the high number is a pretty small population — thus, the classification as Critically Endangered.

The lynx’s habitat has shrunk from 15,700 square miles in the 1950s to just 460 square miles, estimated in 2005. Like its North American counterpart, the Iberian lynx depends on rabbit for sustenance, but the cats’ bunny meal, the European rabbit, has gone through a major decline because of disease, hunting, and habitat loss. The lynx have also suffered from people trapping and poaching them, and hitting them with cars. (Generally cars and wild cats do not mix well.)

The good news for the lynx is that they have a lot of fans and conservation efforts have been well funded. There have been captive breeding programs, work towards restoring their bunny prey, and other efforts to make the world more friendly to the Iberian lynx, all in the hope that the cat population can grow larger, or at least not die out.

The problem, say researchers in the new study, is that none of these plans account for climate change. When they created a computer model of the lynx and rabbit populations that included the expected alterations to temperature and precipitation, they discovered that the lynx would die out within the next 50 years.

“Our models show that the anticipated climate change will lead to a rapid and dramatic decline of the Iberian lynx and probably eradicate the species within 50 years, in spite of the present-day conservation efforts. The only two populations currently present will not be able to spread out or adapt to the changes in time,” coauthor Miguel Araújo, an ecologist at the University of Copenhagen, said in a statement.

All hope is not lost yet, though. If policymakers incorporate climate change into their plans for the lynx, the cats can survive, the scientists say. If climate change were considered in the planning of reintroduction efforts, those efforts could result in there being as many as 900 Iberian lynx by 2090.

The establishment of wildlife corridors along climate pathways might also help. The research team cautions, however, that the immediate nature of the threat, high costs of the corridor creation, and the fact that translocating lynx is technically feasible means that it’s probably easier to just move the cats rather than try to get them to move on their own through a corridor.

“The risk of extinction faced by Iberian lynx within the next 50 years is high,” the researchers write. But with good planning, extinction of the lynx might still be avoided.


Images Credit: Hector Garrido, CSIC Andalusia Audiovisual Bank, via EurekAlert

Rare Lemur Spots Danger By Listening To Other Species’ Alarms

394px-Lepilemur_sahamalazensis_bYou’ve probably never heard of the Sahamalaza sportive lemur (Lepilemur sahamalazensis). The Madagascan species was only discovered in 2006, living in a tiny area on the northwest coast of the island off Africa. Though the lemur’s home recently received protection, the animals are threatened by agriculture and charcoal production. And their rareness prompted the IUCN to move the sportive lemur into the Critically Endangered category just this month.

Unlike some other more familiar lemur species, like the ring-tailed lemurs often seen in zoos, Sahamalaza sportive lemurs are solitary critters that are active at night. During the day, they rest outside tree holes or among tree tangles. It lets them soak up the sun, but staying out in the open also makes them vulnerable to predators, such as the Madagascar harrier hawk, a cat-like carnivore called a fossa, and — perhaps — the Madagascar tree boa. Plus, there are human poachers to worry about.

How do the lemurs manage to keep an eye out for all these threats? They listen to other species that are on the lookout for them, say researchers led by the Bristol Conservation and Science Foundation in the UK. They report their findings in PLOS One.

The scientists traveled to the Ankarafa Forest in the UNESCO Biosphere Reserve and National Park on the Sahamalaza Peninsula in Madagascar to study the lemurs in their home territory. The researchers found 19 Sahamalaza sportive lemurs and, between September and November 2011, played the primates recordings of the vocalizations of other species and watched how the lemurs reacted. Those calls were from two birds, the Madagascar magpie-robin and the crested coua, and another lemur, the blue-eyed black lemur. The researchers played alarm calls that warn of predators as well as sounds the birds and lemurs make when coming into contact with each other, called contact calls.

When the sportive lemurs heard the playbacks of alarm calls that warn of an aerial threat, they became more vigilant and began looking up into the sky. But when they heard terrestrial alarm calls or contact calls, the lemurs didn’t react. (The researchers aren’t sure if the Sahamalaza sportive lemur’s non-reaction to the terrestrial alarm calls mean that they don’t recognize them as a sign of danger or that they decided that it’s just not worth their time.)

“Our results indicate that the Sahamalaza sportive lemur is capable of gleaning information on predator presence and predator type from the referential signals of different surrounding species,” lead author Melanie Seiler, of the Bristol Zoo and the University of Bristol, said in a statement. “Examples for cross-species semantics in lemurs are rare, and this is the first record of lemurs using information across vertebrate classes.”

This ability to listen in on other species is especially important for a solitary creature like the Sahamalaza sportive lemur, the scientists say, because these animals can’t rely on a group of buddies like the ring-tailed lemur can. If they want to avoid predators, eavesdropping can give this sportive lemur a heads up on some of the dangers they face.

Image courtesy of R. Hilgartner, via wikimedia commons

Human Presence Takes A Toll On Galapagos Sea Lions

sea_lionWhen you think about the Galapagos Islands, there are a few things that come to mind. There’s Charles Darwin, of course, and the studies he made there that contributed to his development of the idea of evolution. And the amazing wildlife, including tortoises and iguanas and a whole host of birds. What you don’t think of are things like pollution and invasive species, but these are growing problems, especially in the areas inhabited by humans.

Some islands are still pristine, though, and that gave a group of biologists, led by the Zoological Society of London, a chance to see how one species, the Galapagos sea lion, is affected by the presence of humans. The researchers compared immune activity and body condition of two populations, one in Bahia Paraiso on the undeveloped island of Santa Fe and another that lives in the center of the rapidly growing town of Puerto Bazquierizo Moreno on San Cristobal. The study was published last week in PLOS One.

None of the animals appeared to have signs that they were sick, but those that lived in town had more active immune systems. And among the pups in that colony, those that had higher levels of antibodies had thinner skinfolds and were skinnier.

“A tell-tale sign of an unhealthy sea lion is a thinner than normal layer of blubber, which is what we saw in the sea lions on San Cristobal,” study coauthor Paddy Brock of the ZSL said in a statement. The more active immune systems could indicate “a threat of infectious disease, which could mean human activity is increasing the chance of potentially dangerous diseases emerging in the Galapagos sea lion,” Brock said.

Puerto Bazquierizo Moreno does not seem like it would be a great place to be a sea lion. The bay is home to more than 200 boats and filled with fecal contamination from the vessels and sewage from the town. And the land has a bunch of animal threats, including people’s pets, feral cats and rats. If these factors are impairing the immune systems of the sea lions that live in the area, the impaired immunity could reduce the marine mammals’ ability to hunt, the researchers say.

And the Galapagos sea lions don’t need anything else to hamper their survival. The species was listed as endangered by the IUCN after its already-small population declined by more than 50 percent in the last three decades. The sea lions, which are a bit smaller than the more familiar California species, are not afraid of humans and like to hang out on rocky shorelines and sandy beaches (above). That can put them in direct contact with the human population and make them vulnerable to threats like uncontrolled dogs that will kill sea lion pups.

These sea lions have figured out ways to deal with some threats — they’ve been known to mob Galapagos sharks that approach their rookeries — but they haven’t yet evolved to deal with the ones humans have brought to them. Their immune systems didn’t evolve to exist in a sewage-filled, pet-dominated environment. And it appears that’s put them at even more risk of disappearing from the planet.

Image credit: ZSL_Paddy Brock, via EurekAlert


The Gene That Gives One Breed Of Cat A Curly Coat


Depending on how cat mad you are, you’ve probably never seen a Selkirk rex kitty, let alone seen or held one. They’re not a popular breed — far less than the Persian (b, in the picture above) or the Scottish fold (c) — but their main feature is a curly coat (a, left). The curly trait is dominant, so about a quarter of any Selkirk rex litter will be the less-wanted straight-hair variety (a, right).

The Selkirk rex is a very new breed, having been developed after a curly-coated (aka rex) mutation arose in a cat in 1987. There have been about 8.4 generations of these kitties, which have been outbred to British shorthairs, exotic shorthairs and Persians to establish the breed (without too much inbreeding).

Though scientists (and breeders) have known that the curly trait is dominant, they hadn’t been able to find the responsible gene. The latest — and successful — attempt comes from a team led by Barbara Gandolfi at the University of California Davis. They published their results in Scientific Reports.

The team looked at the genes of nine curly coated Selkirk rex cats and 29 control kitties, a group that included Persians, British shorthairs and straight-haired Selkirk rex cats. The cats may look different, but they all belong to a big group of related kitties known as the “Persian family.” Gandolfi’s team eventually traced the curly trait to a gene KRT71 — they’re not sure exactly what the gene does, but they know it has something to do with the development of the hair follicle (not exactly surprising).

KRT71 had been ruled out as the curly coat gene in the Selkirk rex in an earlier study that looked at curly-coated cats of several breeds, but it seems that the Selkirk rex in that study was a straight-haired cat, so the researchers would have never been able to find a curly coat gene in it. That study did find, though, that various mutations in KRT71 produced curly hair in the Devon rex breed and the naked look of the sphinx cat.

What else might mutations in this gene produce? Scientists still have a couple more curly-haired breeds to check out — the LaPerm and the American wirehair. Perhaps they’re KRT71 mutants as well.

Photos by Barbara Gandolfi, via Creative Commons license: Gandolfi, B. et al. A splice variant in KRT71 is associated with curly coat phenotype of Selkirk Rex cats. Sci. Rep. 3, 2000; DOI:10.1038/srep02000 (2013).

A Scientist Tried To Determine Whether Mice Like Art


Scientists study a lot of crazy things, but it’s rarely that I look at a study and think it must have been a joke (not unless it’s April 1st). But this weekend I found “Preference for and discrimination of paintings by mice” by Shigeru Watanabe of Keio University in Tokyo, which was published last week in PLOS One.

It’s real.

The experiment begins with a box with three rooms. Two of the rooms each had a transparent wall behind which was an iPod that cycled through 10 images, changing the image every 10 seconds. The first test had paintings from two abstract artists, Kandinsky in one room and Mondrian in the other. Over a six-day period in which mice lived in the three-roomed box, only one mouse out of 20 spent more time in one of the artist’s rooms over the other; he preferred Kandinsky. The experiment was repeated with paintings from Renoir, an impressionist, and the cubist Picasso. Again, one mouse preferred one artist (Renoir), but the rest did not.

Watanabe was able to show that the mice could distinguish between two artists by conditioning them to associate a shot of morphine with works by one artist. When placed in the three-roomed box, they spent more time in the room with the paintings that they had once received morphine upon viewing. When they aren’t conditioned, though, mice appear not to care about art.

What you might find even more surprising is that this is not the first time that Watanabe has done a study like this. In his introduction, he summarizes similar studies he has made of birds, including a study of Java sparrows in which “six of seven birds preferred cubist paintings to impressionist paintings,” and several findings in pigeons. “Pigeons can discriminate paintings by Monet from those by Picasso, paintings by Chagall from those by Van Gogh, and Japanese paintings from impressionist paintings,” he writes. He has “also shown discrimination of ‘good’ and ‘bad’ children’s paintings by pigeons.”

Huh. Though this does leave me wondering how in the world Watanabe distinguished between “good” and “bad” art done by kids — even parents have a hard time doing that.

Image (Picasso’s Nude Standing by the Sea at the Metropolitan Museum of Art) courtesy of flickr user Wally Gobetz