I'm continually receiving messages about the fascinating worlds of other animals. Two new reports, one from observations of a chimpanzee and an orangutan swimming and the chimpanzee diving for food and a very interesting quantitative study of birds who are aware of speed limits, are among those worth noting.
It's often been thought that nonhuman apes can't swim. However, we now know this isn't so. In a paper called "Swimming and diving behavior in apes (Pan troglodytes and Pongo pygmaeus): First documented report" published in the online edition of the American Journal of Physical Anthropology and summarized here, we learn that a chimpanzee named Cooper has been observed swimming and diving for food in a pool in Missouri, and an orangutan named Suryia, living in a zoo in South Carolina, was seen swimming almost 40 feet. Both used a modified breaststroke rather then the dogpaddle typical of other mammals.
What these observations have to say about what's called the "aquatic ape hypothesis" (see also) of human evolution remains unclear, but we need to remain open to learning more about the surprising behavior of other apes. According to one of the co-authors on the research paper, Nicole Bender at the University of Bern (Germany), "The behaviour of the great apes in water has been largely neglected in anthropology. That's one of the reasons why swimming in apes was never before scientifically described, although these animals have otherwise been studied very thoroughly. We did find other well-documented cases of swimming and diving apes, but Cooper and Suryia are the only ones we were able to film. We still do not know when the ancestors of humans began to swim and dive regularly."
Birds who know speed limits
Birds are also on the agenda. In a paper published in Biology Letters called "European birds adjust their flight initiation distance to road speed limits", Canadian researchers Pierre Legagneux and Simon Ducatez report that "birds adjust their flight distance to speed limit, which may reduce collision risks and decrease mortality maximizing the time allocated to foraging behaviours." More specifically, "where there was a 50-kilometre-per-hour speed limit, birds on the road typically took off when the car was about 15 metres away, whereas on a 110-km-per-hour road, they took off when a car was nearer 75 metres away. They did this even when faced with a car travelling faster on the slow road or slower on the fast road." Legagneux and Ducatez believe the birds treat cars as predators.
How the birds accomplish this remains unknown but it's clear they have evolved rather sophisticated cognitive skills. For more on birds see essays published in Psychology Today by John Marzluff and Tony Angell under the heading "Avian Einsteins".
The teaser image of Cooper can be seen here.