Why would two stubby-legged, blue-tongued Australian reptiles want to stay together not just for a mating season, but for decades? A 31-year study of the reptiles has suggested an answer. While newly formed couples are still getting to know each other, lizards in long-term relationships can start mating earlier in the season. And dispensing with the foreplay might give them a reproductive advantage over their casually dating neighbors.
Tiliqua rugosa is a species of blue-tongued skink that’s also called the shingleback, bobtail, pinecone, or sleepy lizard. People may have had time to give the lizards so many names because they don’t move very quickly. In fact they seem prepackaged for predators, with their sausage bodies and tiny appendages. Aside from their armored skin, the only thing going for them is that their tails sort of look like their heads, which might confuse other animals.
What’s more remarkable about the sleepy lizard is its commitment to monogamy. Read More
It’s hard to be a showshoe hare. The northern animals are in a constant race for survival with their predators, always cycling between population booms and busts. In hard years, hares are understandably stressed. And that stress can leave its signature not just on those animals, but on several future generations.
When life is good, populations of showshoe hares (Lepus americanus) can roughly double every year. But the hare’s predators—lynx, foxes, coyotes—also increase in numbers as their food multiplies. Then the hare population crashes: nearly every animal becomes a meal. Predators also lose numbers as their food disappears. This creates a constant cycle of about 8 to 10 years, with predator populations lagging a year or two behind hares.
This repeating story has one mysterious chapter, though. After hares and their hunters have both crashed, the hares don’t hop back right away. Their numbers stay low for another 2 to 5 years, even though a new generation of hares is born every year. The varying length of this slump is an “enigma,” writes Pennsylvania State University ecologist Michael Sheriff. Read More
No one expects a human infant to slide into the world with a good grasp of grammar. Marmosets, another kind of chatty primate, are also poor conversationalists when they’re young. But their parents seem to teach them how it’s done. Young marmosets learn the cardinal rule of having a conversation: don’t interrupt. And if they mess up, their parents give them the silent treatment.
Common marmosets (Callithrix jacchus) live in large family groups in the forests of Brazil. “Because marmosets live in dense forests and are very small, it is difficult for them to maintain visual contact,” says Cory Miller, a psychologist and neuroscientist at the University of California, San Diego. So the little monkeys call to each other often, using a variety of yelps, trills, and whistles.
“These vocal exchanges are essentially social interactions,” Miller says. So there are rules about how they should go, just as there are unwritten rules in human social interaction—say please and thank you, don’t stand too close, use your indoor voice. Read More
If you’re a small animal in a cold environment, being standoffish is a bad survival strategy. That’s why animals of many kinds huddle for warmth. They put their furred or feathered bodies right up against their neighbors’ and conserve energy that they would otherwise spend heating themselves.
One especially adorable huddler is the degu (Octodon degus), a rodent that lives in Chile and has a tail like a paintbrush. As temperatures drop, degus clump into cuddling groups to keep warm. A new study finds that degu huddles have no leaders: the animals are perfectly self-organized. In fact, they’re so self-organized that they resemble water crystallizing into ice. Read More
Run-ins are on the rise between coyotes and city-dwelling humans, and scientists aren’t sure why. Now researchers in Alberta think they’ve found a piece of the puzzle. Coyotes are more likely to creep into human spaces if they’re unhealthy.
Conflict between humans and coyotes has increased during the last 20 years, write University of Alberta graduate student Maureen Murray and her coauthors. Yet coyotes were expanding their range for decades before that. They’ve spread to inhabit nearly every part of North America. What makes some coyotes today march downtown and ride the light rail while others stay in a city’s fringes and parks, never meeting a person?
To explore the question, the researchers captured 21 wild coyotes in Edmonton, Alberta over the course of three years. They fitted the animals with GPS collars to track their movements. Read More
I never pass up a robot race. I can say this because I have heard of exactly one robot race ever, and I did not pass it up.
On April 12 I attended the Robot Race and Human 5K, sponsored by Vecna Cares. This was actually two separate races, a human 5K followed by a robot 100-meter dash. Or a 100-meter slow crawl, depending which robot we’re talking about. Or a 50-meter roll followed by a dead stop. Read More
Even if you think your parents played favorites among you and your siblings, they probably weren’t as blatant as a wasp mother. Unless maybe they put your sister in a locked, secure room and fed you to mountain lions.
To be fair, a queen paper wasp (Polistes chinensis antennalis) is a single mom with a lot on her plate. She sets off alone in the spring, after mating, to found a new colony. She mixes her spit with plant fibers to make a pulp that she shapes into a house of delicate, hexagonal rooms. Then she lays her eggs in the cells and waits.
Eventually her eggs hatch into helpless larvae. Later, those larvae spin cocoons to seal themselves inside their cells while they metamorphose into adults. The developing young are vulnerable whenever their mother flies off to find more food. Neighboring wasp queens like to visit an unguarded nest, snatch a baby from its cell, and bring it home to carve up and feed to their own young. Read More
It’s a shame snakes can’t appreciate irony. If they could, sea snakes in Australia might find some humor in their situation. Despite living in water, they seem to spend much of their time desperately dehydrated.
The true sea snakes, or Hydrophiini, include more than 60 species of almost frighteningly well-adapted reptiles. They swim with a graceful, ribbon-like motion through coastal waters around the Indian and Pacific Oceans. They have a venomous bite. Like many other snakes, they give birth to live young. (If you’re curious about what this looks like, there’s a video of a garter snake mom extruding some babies at the end of this post.)
The ancestors of these snakes, though, lived on land. Scientists aren’t sure how these formerly terrestrial animals evolved to live full-time in water that’s too salty to drink safely. It had been suggested that salt glands under the snakes’ tongues help them to process seawater. But more recent research showed that sea snakes can be dehydrated in the wild—they’re not getting enough to drink after all.
To find out more, University of Florida biologist Harvey Lillywhite and his coauthors got in a motorboat. Read More
Kelsey Neam was strolling through the trees in Costa Rica and looking for sloths when she spotted something unusual. High on a tree branch, a three-toed sloth was eating leaves at an unhurried pace. It seemed oblivious to three brown jays that perched nearby and were watching it intently. Then one jay scooted closer and plunged its beak into the sloth’s fur.
Neam is a graduate student in ecology at Texas A&M University. She was in the Costa Rican cloud forests to study three-toed sloths (Bradypus variegatus) and where they live. But the interaction she stumbled upon has less to do with where sloths live, and more to do with what lives on them. Read More
Think real estate decisions are hard for humans? Imagine if the house you lived in were also your singles bar, your babies’ nursery, and your shelter from large animals trying to eat you. And, while you were growing up, your food source, as you nibbled away its floors and shingles.
Moths face all these pressures each time they settle down on a plant. That may be why at least one type of moth uses pleasant associations to help with its choices. The plant species where an individual loses its virginity becomes a favorite. Read More