For bonobos, all sex sounds the same
Bonobos, great apes renowned for their sexual promiscuity, copulate for a variety of reasons—to procreate, to strengthen social bonds, to ease tension, and to settle spats between group members. So one would expect that a bonobo engaged in sex might produce a different vocalization for each different social context in which the act was occurring. Not so, according to researchers studying the species' copulation calls in the wild. The scientists recorded calls from 4 adult female bonobos in the Democratic Republic of Congo and found that their acoustic structure did not change whether they were mating with a male or another female. This is surprising because other primates that engage in reproductive and non-reproductive sex typically make distinct calls during each activity, the researchers explained in a recent Ethology paper reporting the results. Bonobo sex calls are likely in the early stages of evolving to fit the various social contexts in which the animals copulate, the authors added.
Deaf millipedes sing to woo mates
Though the insects lack ears, male members of a South African group of giant pill millipedes "sing" to entice females into mating. Researchers have known that millipedes belonging to the genus Sphaerotherium made noise for almost 40 years, but given that the animals are deaf, the purpose of the calls have remained shrouded in mystery. Now, scientists studying the millipedes as well as historical data collected in the 1970s have a hypothesis: Sphaerotherium giant pill millipedes make noise by rubbing together rigid claw parts in order to signal their amorous intentions to females, which often curl into the defensive posture that gives the insects their name when approached by other animals. The researchers, who report their findings in the journal Naturwissenschaften, reason that though the millipedes can’t hear the species-specific calls, they may be able to feel them using tiny hairs on their legs usually used to detect vibrations made by prey. “Females probably recognize the vibrations of the male,” Thomas Wesener of German’s Alexander Koenig Research Museum and coauthor of the study told Wired Science.
Hummingbirds shake to stay dry
Drying off is a crucial consideration for birds that can weigh as little as an eighth of an ounce. And researchers studying Anna's hummingbirds have recorded, for the first time, how the tiny birds do it—they shake, much like a dog would do after being doused with the hose. "Everybody in the laboratory was astonished when we showed them the video," University of California, Berkeley, biologist Victor Ortega-Jimenez told Wired Science. "It was an unexpected discovery." Ortega-Jimenez and UC Berkeley colleague Robert Dudley used high-speed cameras to film hummingbirds under a sprinkle of water and found that they perform, in mid-flight, rapid shakes of their heads and bodies to shed excess water. Their experimental animals were capable of twisting their heads more than halfway around at a rate of about 132 times per second, all while continuing to beat their wings several dozens of times per second.
Birds of prey dress in drag
Some male marsh harriers, hawk-like birds that inhabit wetlands in western France, are colored almost exactly like female members of the species. Sexual dimorphism, or bodily appearances that differ between males and females of a species, is common in animals and especially birds. But only marsh harriers and one other species of bird contain males that wear female plumage for their whole lives. Researchers studying the potential adaptive advantage of this strategy report, in a recent issue of Biology Letters, that normally-colored male harriers aren't as aggressive towards the female mimics. This may give the disguised males unique access to territories and mates, as they are less likely to engage in territorial battles common among normally-colored males.
Hagfish go beyond scavenging
The slimy, jawless hagfish is commonly considered a deep sea scavenger, burrowing into whale carcasses and other deceased delicacies that descend to the ocean floor from above. But researchers from New Zealand and Australia have captured the first ever video footage of hagfish actively preying on another live fish. In footage that lasts about 2 minutes, a hagfish in waters off of New Zealand captures a red bandfish by invading its burrow, suffocating it with the slime that it also uses to deter predators, and grasping the fish with its nightmarish dental plates. The authors of the paper revealing the findings, published last month in Scientific Reports, suggest that hagfish have likely been successful across 300 million years of evolution thanks to an underappreciated suite of behaviors such as this.