animal behaviour

Baby turtles work together to dig themselves out of a nest hole

Baby sea turtles work together to dig their way out of sandy nests, and the more of them there are, the less energy they use doing it.

We knew of this group-digging behaviour, called social facilitation, for a long time, but the reasons for teamwork were unclear. Possible explanations included speeding up nest escape or helping the turtles emerge together to swamp awaiting predators on the beach. Read more in New Scientist.

Clawing Their Way to Victory

Research suggests fiddler crabs with regenerated claws have distinct fighting strategies.

Male fiddler crabs have one oversized claw, which they use to both attract females and to fight other males for the best breeding burrows on the beach. These fights can get violent, and crabs will sometimes lose their big fighting claw in the process. Fiddler crabs have the ability to regrow their claw, though the new one will never be as sturdy as the original, says Daisuke Muramatsu, a biologist at Kyoto University in Japan.

Even in their weakened state, the crabs must fight. Yet based on his new research, Muramatsu argues that fiddler crabs are more strategic fighters than we’ve given them credit for: he says they pick battles that account for their handicap, and use a strategy of bluff and counter-bluff to end disputes before they begin. Read more in Hakai.

Alligators help protect bird nests – but still snack on chicks

It’s raining food for alligators in the Everglades – those that act as bodyguards for nesting birds get paid in chicks.

It’s not uncommon for one animal to gain protection from a neighbour. In Florida’s Everglades, wading birds like storks and egrets preferentially build their nests where alligators live, because the presence of the big reptiles protects them from nest-raiding racoons and opossums.

Lucas Nell of the University of Florida in Gainesville has now cruised the Everglades at night to see what the alligator bodyguards get out of the deal. Read more in New Scientist.

Wild gorillas compose happy songs that they hum during meals

Gorillas sing and hum when eating, a discovery that could help shed light on how language evolved in early humans.

Singing seems to be a way for gorillas to express contentment with their meal, as well as for the head of the family to communicate to others that it is dinner time. Read more in New Scientist.

White shark’s diet may include biggest fish of all: whale shark

White sharks are voracious predators, and it seems they even set their sights on the biggest fish in the sea. Two vertebrae recovered from the stomach of a 4.5-metre-long white shark caught 50 years ago show that it had been feeding on a whale shark, and a big one at that. It was around 8.5 metres long, the size of the vertebrae suggests. Read more in New Scientist.

Floral Smells Stop Stinging Bees

bee picAppetizing scents can override alarm signals in honeybees.

As an amateur beekeeper, I’m resigned to getting more than my fair share of painful stings when harvesting honey, or even cutting the grass too close to the hive. But new research published today in Nature Communications shows that there may be a way to distract angry and defensive bees and reduce the number of times clouds of vengeful insects send me fleeing to the house. Read more in Inside Science.

Why fruitflies know their beer

Competing neuronal pathways help adults to choose locations with just the right amount of alcohol for their offspring to thrive.

Fruitflies know exactly how much alcohol will be good for their young. Larvae living on a food source with the right concentration of ethanol will grow into heavy, healthy adults and will be protected against parasites — which explains why the insects are attracted to rotting fruit or the crate of empty beer bottles in your kitchen but not to the vodka or gin.

Now researchers have uncovered the neural mechanism that allows the fruitfly Drosophila melanogaster to choose the best place to lay its eggs. Read more in Nature.

Smelly microbes help hyenas to communicate

Bacteria in scent glands give information about hosts’ species, sex and reproductive state.

The hordes of microbes that inhabit every nook and cranny of every animal are not just passive hitchhikers: they actively shape their hosts’ well-being and even behaviour. Now, researchers have found evidence that bacteria living in the scent glands of hyenas help to produce the smells that the animals use to identify group members and tell when females are ready to mate.

Kevin Theis, a microbial ecologist at Michigan State University in East Lansing, had been studying hyena scent communication for several years when, after he gave a talk on the subject, someone asked him what part the bacteria might play. “I just said, ‘I don’t know’,” he says. He started investigating. Read more in Nature.

Bats use ear trumpets for social calls

Mammals roost in megaphone-shaped leaves that amplify calls from friends.

Bats that nest inside curled-up leaves may be getting an extra benefit from their homes: the tubular roosts act as acoustic horns, amplifying the social calls that the mammals use to keep their close-knit family groups together.

South American Spix’s disc-winged bats (Thyroptera tricolor) roost in groups of five or six inside unfurling Heliconia and Calathea leaves. The leaves remain curled up for only about 24 hours, so the bats have to find new homes almost every day, and have highly specialized social calls to help groups stay together. When out flying, they emit a simple inquiry call. Bats inside leaves answer with a more complex response call to let group members know where the roost is. Read more in Nature.