| MadSci Network: Zoology |
Animals certainly have a body clock but so far all the evidence is that this is linked to a circadian (daily) rhythm. For instance animal studies (eg Morgan's work on hamsters) have shown that part of the brain, the suprachiasmatic nucleus (SCN) of the hypothalamus, plays a central role in the daily cycle by regulating an internal oscillator and synchronizing it to the changing cycles of day and night (using cues like light) and of body state. This biological clock drives the daily expression of vital functions as diverse as feeding, drinking, body temperature, and neurohormone secretion. Most research has focused on these daily rhythms - I have found little on time perception in animals. However, in a Daily Telegraph article by Highfield on 21 February 1996, he points out that humans have an internal interval clock used to measure duration. Another area of the brain, the striatum, is reponsible for timing short intervals. Also very recent work by Onoe et al, reported in Neuroimage, January 2001, has shown changes occur in cerebral blood flow in the prefrontal cortex and basal ganglia when monkeys carrying out time discrimination tasks. These structures appear to be part of a neural network used for time perception. Finally, structures like the striatum and basal ganglia are known to damaged by Parkinson's disease and sufferers are poor at estimating time. Therefore as dogs also have these brain structures I would assume they can perceive intervals of time. Certainly in the case of Guide Dogs leading blind people over the road - the dogs can certainly be trained to judge the time needed to cross the road safely.
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