When I finally peeked over the gumbo knob, at least 70 antelope came into view, bedded in the sanctuary of a remote stream valley. Blessed with telescopic vision, pronghorns feel safest in places like these, open flats where they can see danger coming for miles.
I glassed the herd, but one animal stuck out. It was a mule deer, bedded in the very midst of the antelope herd.
Pronghorns and mule deer occupy the same general habitat but usually prefer different terrain. My guess is that this deer was well aware of the antelope's visual acuity and was benefiting from their early-warning system. If danger entered this valley, the antelope would know it first and flare, and the deer could flee in their wake.
Ungulates don't have a corner on this sort of cooperation. One of the most studied symbioses is that between forest-dwelling rodents and grizzly bears. In high-elevation white pine forests, chipmunks and ground squirrels spend vast amounts of time and energy gathering the high-protein nuts from these pine trees, collecting them in caches hidden in root cavities and in underground burrows. Like a squirrel's buried acorns, these pine nuts are a favorite winter food supply.
Grizzly bears have learned this and spend much of their fall finding and raiding these pine nut caches, a critical food supply as they prepare themselves calorically for hibernation. In years when other food sources are in low supply, the squirrels' loot can mean the difference between a bear's survival and starvation.
This notion of different animals benefiting from each other's particular talents reminds me a bit of Aesop, the ancient collector of fables who often personified animals to comment on human nature. His fables run the gamut from the slow but steady tortoise and the hurried hare to the meek mouse that extracts the thorn from the prideful lion's foot.
One element missing from many of these tales - and in nature, too - is the notion of reciprocity. The mule deer and the grizzly bear both benefit from their hosts, but I'm not sure how much they give in return.
Columnist Andrew McKean can be contacted at firstname.lastname@example.org.