Seal Versus Sea Lion

A publication that will remain anonymous here (since I hope to write for them one day), mixed up seals and sea lions on Twitter today. It’s easy enough to see why — they start off the same when you’re typing, and if you’re not paying attention, you’ve written one when you mean the other.

It probably also doesn’t help that they’re both marine mammals — pinnipeds, in fact — that look quite similar (seal on the left, sea lion on the right):seal-sealion Sea lions and true seals (I’m going to ignore fur seals to make this a little less confusing) are separated by some 28.5 million years of evolution, according to TimeTree. The two animals are now in separate families, Otariidae (sea lions) and Phocidae (seals). There are many different species of both seals and sea lions, but all these animals have a basic, similar body shape: streamlined with flippers instead of feet.

But look closer and you’ll find subtle differences. The front flippers on seals are small, stubby, and hairy, with claws. Their back flippers don’t rotate but instead let seals be efficient swimmers. Sea lions have longer, skin-covered front flippers and back flippers that they can rotate underneath them, letting them walk, or at least shuffle about, on land. That makes sea lions the animals you’re most likely seeing basking on a rock at the zoo.

True seals sometimes have the name the “earless” seals because they don’t have anything covering the holes that lead into the hearing apparatus in their heads. Sea lions, though, have small flaps that cover their ear holes. There are also some differences in the whiskers, but I doubt many of us will ever get close enough to one of these animals to tell the difference.

Sea lions are also more vocal and more social than seals. Perhaps that means that sea lions are extroverts and seals are introverts.

Image credit: NOAA

Got Deer In The Backyard? If You Were In India, You Might Have Leopards

leopard

Here in the U.S., we complain about deer and bunnies munching on our gardens. In some places, people have to worry about more dangerous carnivores like coyotes, wolves, or bears. Where people and nature meet, conflict is often the rule.

In India, they’ve got animals such as leopards and hyenas to worry about. But where one might expect conflict, that isn’t a given, as demonstrated in a study published last month in PLOS One.

The study comes from a group of researchers led by the Wildlife Conservation Society-India who used camera traps to track leopards (Panthera pardus) and striped hyenas (Hyaena hyaena) in western Maharashtra (central India), an area that is rural and where most of the people are farmers growing sugar cane, millet, and vegetables. The cameras captured a number of leopards and hyenas over a one-month period in late 2008, and using those pictures, the researchers were able to calculate that there were about six leopards and five hyenas per 100 square kilometers. (For comparison, there were 100 wolves in Yellowstone National Park in 2011, or about 1.11 wolves per 100 square kilometers.)

Normally leopards in India live off of prey like cheetal and langur, but these smallish animals aren’t found much in this part of the country. Instead, the big cats are surviving on a diet of domestic dog and livestock, the researchers say.

In some places in India, leopards have been found preying on humans, but in western Maharashtra, there have been no fatal conflicts. This is particularly notable because the human population density there is very high — 300 people per square kilometer — and the cats were photographed on human trails, so they are definitely coming near the human population.

Why would there be little conflict?

“The crux of the issue to me is one of tolerance,” study lead author Vidya Athreya writes on the Project Waghoba website. “In many talks in cities, I often ask the public which of them would let be a leopard that is coming to their lane only to get dogs and has never harmed people. I do not think a single hand has ever been raised. However in rural India, tolerating other forms of life is a part of their lifestyle, be it domestic animals or wild.”

But beyond a lesson in tolerance, by showing that what might be considered dangerous wildlife can live near people without harming them, this study calls into question the perceived necessity of moving wildlife like leopards. Leopards that are found near human populations are now often treated as strays and moved to protected areas, the researchers say. But these translocated cats have attacked people near the sites where they are released. If they are less deadly when left in place, perhaps they should be left alone.

But I do wonder how well the local people deal with the loss of their dogs and, especially, their livestock, which is an issue that’s not addressed by the researchers. I imagine that for some poor farmers, losing even one animal can be a devastating financial loss. Any program to protect carnivores really needs to have some sort of scheme to insure people against livestock losses to give the humans less of a reason to kill these wonderful creatures.

Image (camera trap photo of a leopard from the study) credit: Project Waghoba

Vervet Monkeys Use Patience To Solve A Game, But Could Humans Do It?

monkeyThe game is called the “Forbidden Circle.” A group of researchers from the Netherlands and France, in a study published in Current Biology, trained a vervet monkey — a small, black-faced species common in East Africa — to open a container of yummy fruit only when other members of her group, those dominant to her, stayed outside an imaginary circle, about 10 to 15 meters away.

The other monkeys weren’t trained on the rules of this game. They didn’t know that the container could only be opened when they weren’t near. So at first, the dominant monkeys tried to guard the food, a strategy that in normal life would likely get them some fruit. But the provider monkey wouldn’t open the container, as per the rules, and eventually the monkeys would wander off. When they’d all left that imaginary circle, the container would be opened and they all could feast.

After several rounds of the game, however, the monkeys started to figure it out, realizing that trying to guard the container wouldn’t get them the food and that they had to move away if they wanted to eat. Higher ranked monkeys learned the rules first, and their lower ranked compatriots followed. And once they learned the rules, the monkeys remembered them, even when they hadn’t played the game for more than six months.

What’s even more interesting is that the monkeys learned the rules solely through trial and error, and they didn’t communicate the rules to each other or punish one another if the rules were broken. All it took was time and quiet patience.

“The vervets show us that tolerance towards group members and patience while others are learning how they can improve things individually can go a long way in solving coordination problems,” co-author Ronald Noë of Université de Strasbourg in France said in a statement.

This imaginary circle game hasn’t been tried yet on humans, but I have to wonder whether we could pull it off with so little drama. Just think of those team-building activities that take place during staff retreats than end in arguments and bullying and, sometimes, tears — it’ll make you wish you had a vervet monkey for a co-worker.

Image credit: Current Biology, Fruteau et al.

No Easy Solutions For Saving Africa’s Wildlife

elephantA sampling of recent stories from Africa:

Dozens of elephants were slaughtered in Chad in just a week. Then there was a study that estimated 62 percent of central Africa’s pachyderms were killed between 2002 and 2011. And a report that 80 percent of the water buffalo in the Serengeti have been lost to poaching, along with 2,000 elephants and nearly all the rhinos. The United Nations Environment Programme says that 22,218 great apes, more than half chimpanzees, have been killed since 2005.

In a rare spot of good news, six rare white rhinos were secretly transported to Botswana to escape rampant poaching in South Africa. But that’s just a drop in the bucket when two dozen rhinos can be killed in a week.

Thousands and thousands of iconic wildlife are killed each year in Africa, and I can’t help but think that the problem is getting worse.

There are plenty of suggestions for how to stop the tide: Legalize trade in rhino horn. Build fences around lion habitat. Slick ad campaigns and a multi-national anti-poaching force. But what strikes me about all these proposals and plans is that they don’t get to the heart of the problem — greed.

As long as the money to be made through the wildlife trade outweighs the risks and punishments, poaching will continue.

Those caught poaching animals or trafficking in their remains are often let off with little more than a slap on the wrist, usually just a fine. A Chinese ivory smuggler, for example, was fined all of $350 for a haul worth $2,500 before being set free. Punishment in the U.S. for these crimes can be more harsh — a father and son team of rhino horn smugglers faced a fine of up to $1 million in one case last year — but I do wonder how much of that was for tax evasion rather than wildlife trafficking. And though there are a few countries where poaching and smuggling can bring a sentence of jail time, convictions can be rare.

Calls for Google to remove ads for ivory are at least trying to get at the root of the problem. While there is a market for things like ivory and rhino horn and lion parts, there will be people willing to kill elephants and big cats and other amazing creatures.

But how do you fight a rumor that rhino horn will cure cancer? Or that lion bone will increase a man’s sex drive? That God wants to you wear ivory? That a chimp bone will make a child stronger?

Fences may help keep lions or elephants from straying into villages, but it won’t stop a determined man with a gun from trying to make a few thousand dollars. Legalizing trade in animal parts isn’t going to stop demand for them. Slick ad campaigns won’t deter someone who truly believes they’ve found a cure for the disease that’s killing them. And building up an army of anti-poaching forces can’t protect every animal on the continent, especially when there are still legal options (i.e., trophy hunting) for obtaining wildlife.

What we need, around the world, is better laws against the wildlife trade, better enforcement of these laws, and harsher punishments attached to wildlife crimes. And we should promote projects that give local people incentive to protect the wildlife around them, such as through ecotourism.

Because it’s only when we change the equation such that an elephant or a rhino or a lion is worth more alive than dead that the killing will stop.

Image of a poached elephant carcass in Cameroon in 2009, courtesy of flickr user USFWS Headquarters

Male Lions Are Ambush Hunters

LionsFemale lions are known to be great hunters, cooperating to bring down their prey. Male lions, in contrast, have reputations for being great moochers, living off the kills of the females in their prides. That reputation is undeserved — males do indeed hunt — but it seems that they take a different hunting tactic, finds a study published in Animal Behaviour.

Researchers from the Carnegie Institution of Science in Stanford, California, and the University of Pretoria in South Africa matched airborne measurements of vegetation cover in South Africa’s Kruger National Park with GPS telemetry of lion kills. They found that male lions tended to kill in areas that had shorter lines-of-sight than where they rested (lions, being cats, spend most of their time resting), especially at night. But there was no difference with females.

They concluded that the male lions were taking advantage of areas with lots of vegetative cover to ambush their prey. That difference in technique likely helps male lions to be as successful in their hunting as the females that are using the high-success strategy of cooperation.

Reading through the paper, I wonder if the finding might also account for the males’ undeserved reputation for laziness. Lion studies are much easier in open lands like the Serengeti, and it’s in those places where females’ cooperation is especially noticeable. If the males were hunting off in the brush where scientists weren’t looking, no one would have noticed that the males’ ambush tactics.

But more importantly, the scientists say, the finding might have implications for the management of parks and other wildlife areas.

“By strongly linking male lion hunting behavior to dense vegetation, this study suggests that changes to vegetation structure, such as through fire management, could greatly alter the balance of predators and prey,” study co-author Scott Loarie, of the Carnegie Institution of Science, said in a statement.

Image of lions in Kruger National Park courtesy of flickr user jon|k

Polar Bears Survive Disappearance Of Sea Ice By Moving To Land

polarbear

Polar bears live an incredibly specialized existence in the Arctic. Though born on land, they prefer to live on sea ice, from which they can hunt the seals that make up the majority of their diet. But with sea ice disappearing, there’s been well-founded worry about what will happen to the polar bear (Ursus maritimus).

It might be easy to assume that the bears will give up their icy lives and move to land. And a study of the polar bears of the Western Hudson Bay, published by the Journal of Animal Ecology, has found that the bears do just that — moving onto shore when the sea ice retreats and returning to the ice when it grows again later in the year. By tracking more than 100 female polar bears for over a decade, the researchers found that the bears’ migration could be timed to the movements of the sea ice.

But that time between the sea ice retreat and return has been getting longer and longer as the Arctic warms, with the result that the bears are spending more and more time on land.

“The data suggest that in recent years, polar bears are arriving on shore earlier in the summer and leaving later in the autumn. These are precisely the kind of changes one would expect to see as a result of a warming climate and may help explain some other studies that are showing declines in body condition and cub production,” the study’s lead author, Seth Cherry of the University of Alberta in Canada, said in a statement.

The problem is that on land the bears don’t hunt, or at least not enough to matter; they live off their stores of fat. Subadult bears, like the one above, are particularly vulnerable because, due to their smaller size, they have less fat to rely on. And their survival rate has been dropping. This might also explain the trend in decreasing litter size. Females don’t have enough fat to both survive the long summer and give birth to, and maintain, multiple cubs.

Which all makes me wonder: What happens when the summer gets too long for even the fattest bears to survive?

Image copyright Andrew Derocher, Univeristy of Alberta, via EurekAlert

How Cancer Evades The Devil’s Immune System

devil

In the 16 years since Devil Facial Tumor Disease emerged among the devils of Tasmania, DFTD has devastated the island’s population of these carnivorous marsupials. The infection spreads easily among the violent animals — they bite each other, passing tumor cells from one devil to the next — and DFTD always ends in death.

A devil’s immune system should be able to put up some sort of fight against the cancer cells, but it doesn’t. And a group of scientists led by the University of Cambridge in England now say they know why; they report their findings today in the Proceedings of the National Academy of Sciences.

DFTD cells, they found, don’t express major histocompatability complex (MHC) molecules on their surface. These molecules alert the T cells of the immune system that a foreign cell is foreign. Without the molecules, the immune system doesn’t know it should fight back.

There are two types of MHC molecules — class I and class II. The DFTD cells likely don’t have class II molecules because the cells got their start as Schwann cells, a type of nervous system cell. In humans and rodents, Schwann cells are known to not express class II MHC molecules; it may be the same in devils.

The class I MHC molecules, though, were probably lost later, the researchers say, but not because of a mutation. Instead, these molecules are not expressed because of epigenetic changes that likely occurred years ago when a devil’s Schwann cells transformed into DFTD cells. It’s one of the changes that turned DFTD into such a horrible, dangerous disease.

But the discovery of how DFTD evades the immune system gave the researchers an idea on how they could prime a devil’s immune system to fight the disease: They suggest that modifying DFTD cells to express MHC molecules could work as a vaccine.

Time is running out, though. Already 84 percent of the devil population is gone. And a vaccine may not prove a savior. “Even if we had a perfect vaccine, we’d probably have to vaccinate every animal more than once,” Alexandre Kreiss, a research fellow at the Menzies Research Institute in Tasmania told the New York Times in January. “I don’t see us doing that for the whole population.”

Image courtesy of flickr user quollism

The Wolf That Thinks It’s A Fishing Cat

Bears fishing for salmon are fun to watch, but they’re not exactly unique. Wolves fishing for salmon, though — now that’s a bit more special. The wolf in this video is probably mimicking the bears that he’s hanging out with, but to me, he looks more like a fishing cat than a Fozzie or Teddy.

(HT: @lizabio)

Dear Nature Lover, My Cat Isn’t Your Problem

cat

Thousands of years ago, cats and humans struck a deal. We’d give kitties a home as long as they took care of our vermin. The cats don’t always hold up their end of the bargain — my own, for example, has done nothing about my current mouse situation — but humans haven’t done much better. And now we have a huge problem.

A paper published today in Nature Communications documented a kitty kill tally that’s pretty scary. In the U.S., cats kill as many as 3.7 billion birds and 20.7 billion mammals every year. Culturing Science calls them “ruthless killers.”

They’re right, of course. That’s why we inviting cats into our homes.

But a closer look at the study shows that it’s not cats like mine that are the problem. My kitty never goes outside. But even owned cats that go outside aren’t the worst killers. Unowned, feral cats accounted for 89 percent of the mortality.

And the fault with the feral population lies with us humans. People don’t get their pets fixed. They let them roam free or, worse, abandon them. And well-meaning people feed feral cat populations, letting the animals survive and kill more wildlife.

So what’s to be done? It has to start with a serious conversation about how we care for cats. We need to get more people to spay and neuter their animals, and encourage them to not let their animals outside. (Really, house kitties are happy.) And we have to figure out what to do with feral cats. Trap-neuter-release programs appear humane, but it’s having devastating affects on the natural world.

Ideally, I would gather up all the feral kitties in the world, get them fixed, and let them live out their days in huge barns. That’s probably not practical, but at least it’s an idea.

Image credit: Flickr user Janesdead

Dolphins Help One Of Their Own

Despite Flipper’s reputation for adorableness, dolphins really are dangerous, aggressive animals. That said, there are times when we’re all reminded why they’re known for cuteness.

Kyum Park of the Cetacean Research Institute in Ulsan, South Korea, and colleagues in July 2008 spotted one pod of long-beaked dolphins carrying out a display of particularly bittersweet behavior. According to the story reported in Marine Mammal Science, a female of the group was in trouble. Her pectoral flippers were paralyzed, and she was having difficulty swimming or even staying afloat.

But others in her group soon helped out, trading off swimming with their injured companion, and creating a raft of dolphins to keep her from drowning.

Sadly, they weren’t able to save her. But as she sank, five of her friends stayed with her, touching her body, as if they were mourning her loss.

It’s difficult to assign motives to such actions — after all, we can’t ask a dolphin why it did something — but Karen McComb of the University of Sussex in Brighton, U.K., told New Scientist that rescuing an injured member of the group could help the pod to maintain its territory, preserve shared genes, or maintain the group’s bond. “It makes a lot of sense in a highly intelligent and social animal for there to be support of an injured animal,” McComb said.

Whether the actions constitute empathy is harder to say. But with such feelings sometimes lacking in the human world, it certainly is good to see something like it, even among deadly animals.