Tears for fears. Was Re: Guide for anti-AATers

Bill Burnett (bbur@wpo.nerc.ac.uk)
Mon, 16 Oct 1995 10:47:09

In article <45o2fu$2gl@scotsman.ed.ac.uk> jamesb@hgu.mrc.ac.uk writes:

>1) Humans and elephants are the only land animals that weep when they are
>upset. This feature is shared with examples of marine birds, marine
>reptiles and seals, and elephants and sea-cows are thought to share a
>marine ancestor. Chimpanzess get just as upset as humans do, and have
>complicated social relations which would benefit from having suching a
>signal as crying, but they don't do it. Human stress-related hormones
>aren't any more toxic or harder to excrete than chimpanzee ones, so why
>should we have evolved this excretion route for their break-down
>products? Is it just coincidence that so many marine species cry? I'll
>give up on this if someone finds an animal with no signs of an aquatic
>past that sheds tears when upset.

Marine reptiles at least (e.g. Galapogos marine iguanas, turtles) shed tears
as a salt excretion mechanism. It has nothing to do with emotion. I suspect
the same is true of seabirds and marine mammals. Beavers shed tears as an
aspirin excretion mechanism (too much birch bark in the diet). It has nothing
to do with emotion. Chimpanzees have an amazing behavioural repartoire and
are capable of displaying many emotions quite happily with or without resort
to crying.
YES, both my crying examples are aquatic.
NO, I can't offer an adaptive explanation for human tears though someone else
(I hope) might have some ideas, but let's lose the emotion myth.