!Animal cognition
!!Fish can infer transitive social rank by observation alone
Nature 445, 429-432 (25 January 2007) doi:10.1038/nature05511
Logan Grosenick, Clement and Fernald
Transitive inference (TI) involves using known relationships to deduce unknown ones (for example, using A > B and B > C to infer A > C), and is thus essential to logical reasoning. First described as a developmental milestone in children1, TI has since been reported in nonhuman primates2, 3, 4, rats5, 6 and birds7, 8, 9, 10. Still, how animals acquire and represent transitive relationships and why such abilities might have evolved remain open problems. Here we show that male fish (Astatotilapia burtoni) can successfully make inferences on a hierarchy implied by pairwise fights between rival males. These fish learned the implied hierarchy vicariously (as 'bystanders'), by watching fights between rivals arranged around them in separate tank units.
!!Language evolution: Semantic combinations in primate calls
Putty-nosed monkeys rely on two basic calling sounds to construct a message of utmost urgency.
doi:10.1038/441303a
!!Cultural transmission in Dolphins
Tue Jun 7, 4:24 PM ET
Dolphin mothers in Western Australia teach their daughters how to use a sponge to forage for food, yet another example of how animals learn to use tools.
The animals that used the sponges all seemed to be related, but the researchers could not find any genes associated with the behavior, they report in this week's issue of the Proceedings of the
National Academy of Sciences.
Michael Kruetzen of the Anthropological Institute and Museum at the University of Zurich in Switzerland and colleagues watched the dolphins at work in Shark Bay in Western Australia.
For years researchers have seen the dolphins pick up sponges with their beaks and then use them as they poked along the sea beds, evidently to protect their delicate snouts from spiny fish.
Kruetzen's team analyzed DNA from 13 "spongers" and 172 dolphins that did not display this behavior. While the sponging animals all seemed related along the female line, there was no genetic link.
!!Word Learning in a Domestic Dog: Evidence for "Fast Mapping"
Science, Vol 304, Issue 5677, 1682-1683 , 11 June 2004
doi:10.1126/science.1097859
Juliane Kaminski, Josep Call, Julia Fischer*
During speech acquisition, children form quick and rough hypotheses about the meaning of a new word after only a single exposure—a process dubbed "fast mapping." Here we provide evidence that a border collie, Rico, is able to fast map. Rico knew the labels of over 200 different items. He inferred the names of novel items by exclusion learning and correctly retrieved those items right away as well as 4 weeks after the initial exposure. Fast mapping thus appears to be mediated by general learning and memory mechanisms also found in other animals and not by a language acquisition device that is special to humans.
!!Animal behaviour: Geomagnetic map used in sea-turtle navigation
Nature 428, 909 - 910 (29 April 2004); doi:10.1038/428909a
These migratory animals have their own equivalent of a global positioning system.
Migratory animals capable of navigating to a specific destination, and of compensating for an artificial displacement into unfamiliar territory, are thought to have a compass for maintaining their direction of travel and a map sense that enables them to know their location relative to their destination1. Compasses are based on environmental cues such as the stars, the Sun, skylight polarization and magnetism2, but little is known about the sensory mechanism responsible for the map sense3, 4. Here we show that the green sea-turtle (Chelonia mydas) has a map that is at least partly based on geomagnetic cues.
[[Category.Science]]