Wild Things: Killer Whales, Spiders and Woodpeckers

Lions, orcas, hyenas, some hawks and a few other species hunt collaboratively, and now researchers have added a fish to that list. Yellow saddle goatfish in the Red Sea often congregate. And when one fish starts accelerating toward a prey fish, its associates join the hunt. These “blockers” spread out over the reef to cut off the prey’s escape routes, giving the group of goatfish a better chance at making a successful catch. The behavior was observed by researchers from the University of Neuchâtel in Switzerland. Other species of goatfish eat only invertebrates, while the yellow saddle variety chases mainly other fish. The researchers suggest that collaborative hunting may have evolved in this species to allow the goatfish to exploit a faster and more nimble source of food.

How can a woodpecker repeatedly bang its head into a tree at 15 miles per hour without harming itself? Researchers from Beihang University in Beijing and elsewhere, using high-speed video, microscopic scanning and 3-D models, found that spongy spots in the skull, along with tissues of different sizes in the upper and lower beak, are crucial for absorbing shock. The work might be useful for designing helmets and other safety gear.

Near the end of the last ice age, a group of hunters in Washington State bagged a mastodon. A new Texas A&M University-led study of a mastodon rib—with a projectile point still embedded in it—shows that the animal lived 13,800 years ago. It’s some of the oldest evidence of hunting in the New World, and more evidence that humans arrived well before the Clovis people, once thought to be the first Americans.

In nursery web spiders, a male gives a potential mate an insect wrapped in silk. When a sneaky guy wraps up a fake offering, such as an inedible seed, a female will begin to copulate. But once she detects the deception, she will “terminate mating early for worthless gifts,” says Maria Albo of Aarhus University in Denmark.

Lives: In the Antarctic (a population known as type B), feeding on seals and penguins.
Beelines: Occasionally for the subtropical waters off Uruguay and Brazil, a study documents for the first time. But the trips are so quick they’re probably not for foraging or giving birth. Instead, the trips may be the equivalent of a vacation skin peel.
Returns: Without the coating of algae that tinges its skin yellow. John Durban of the Southwest Fisheries Science Center in La Jolla, California, and his co-author suggest the orcas travel to milder latitudes when they shed their skin “to help the whales regenerate skin tissue in a warmer environment with less heat loss,” he says.