The false killer whale (Pseudorca crassidens) is regarded as Data Deficient globally and in Australia. Further information on distribution, abundance, movements, population structure and mortality rates are required for effective management of the species in the ETA. The re-sightings of marked individuals between sightings and years suggest that at least some individuals exhibit a degree of site fidelity to Gabonese shelf waters. These are the first verified records of false killer whales using continental shelf waters in the ETA, indicating that the species occupies neritic habitat in the region in addition to its previously documented Whistles recorded during one sighting had simple structure, short duration and a mean fundamental frequency of 7.8 kHz. Observations included predation of Atlantic sailfish Istiophoms albicans and two occurrences in proximity to humpback whales Megaptera novaeangliae. Forty-three false killer whales were photo-identified during three encounters on the Gabonese shelf seven individuals were matched between 20, including two individuals that were present during all three sightings. All six sightings were located in continental shelf waters (≤103 m depth) and in relatively nearshore (mean ¼ 13.9 km) habitat. Here we report six false killer whale records from cetacean surveys carried out off Gabon (four records) and Cte d’Ivoire (two records) between 20, providing the first at-sea sightings in those two existing range states. The false killer whale Pseudorca crassidens is currently documented from only six eastern tropical Atlantic (ETA) range states, five of which are evidenced by strandings, by-catch or skeletal remains rather than at-sea sightings and consequently provide no information on habitat or behaviour. You can follow LiveScience senior writer Stephanie Pappas on Twitter Follow LiveScience for the latest in science news and discoveries on Twitter and on Facebook. "This gives us a bigger idea of exactly what is going on underwater between the predator and the prey," she said. Yet-to-be published follow-up research on harbor porpoises suggests that they can focus their echolocation, too, Kloepper said. Nachtigall says it's likely the whales focus automatically, given the sorts of high-speed, dimly lit underwater chases that are required to catch prey. Musculature around the organ probably also contributes to the focusing ability. By forcing air through the melon, false killer whales create their echolocation clicks. The melon is situated above the eyes and is what makes false killer whale and dolphin foreheads bulge. This ability arises from a specialized organ called the melon, Kloepper said. "We're calling it 'acoustic squinting' to help humans better understand," Kloepper said. The ability is not unlike how the human eye works to focus, only with sound instead of light. When her target was farther away or more difficult to differentiate its shape and size, the false killer whale changed the shape of her echolocation beam so that it would be more narrowly focused on the object. What the new study revealed, however, was that Kina is capable of focusing her clicks on an object. None of the humans involved could tell, but Kina knew. In one early experiment with Kina, the machinist who made the metal cylinders made a tiny error, said Paul Nachtigall, Kloepper's doctoral advisor. Graduate student Laura Kloepper with Kina the false killer whale (Image credit: Marcia Kloepper) From 26 feet (8 meters) away, she can detect the difference between two objects that differ in width by the length of a human hair. They were then able to reconstruct the shape of the sound-wave beam coming from Kina using computer software.īy any measure, Kina's detection abilities are "amazing," Kloepper told LiveScience. As she did so, the researchers recorded her echolocation clicks with underwater microphones. Kina couldn't see which cylinder the researchers had lowered into the water, so she had to echolocate to gauge its size. If the cylinder is any other size, she stays put. Kina has been trained to back out of the hoop and tap a paddle in her pen when she detects a cylinder of a certain size and thickness.
#False killer whale series
In the newest study, published today (March 22) in the Journal of Experimental Biology, Kina swam into a hoop and waited for researchers to lift an acoustic barrier between her and her experimental targets - a series of hollow cylinders.
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