Bambi and That Other Guy

We all remember Bambi....

Here's his dad:

(Note the bifurcating growth form of the antlers.)

And here are some of his male cousins:

Disney and his slaves...er...animators...worked in southern California, where the native deer is the Mule Deer, Odocoileus hemionus. So although Bambi (written by German author Felix Salten) was originally a European deer, Disney made him into a Mule Deer (a.k.a., Black-tailed Deer):

But did the Disney people do their homework?

Remember when Bambi fell in love? And then was challenged by another deer for Faline's affections?

Check out the rival's antlers:

Clearly, Ronno (the rival) is a different species, namely a White-tailed Deer (Odocoileus virginianus). His antlers form a circular "crown" (see the image of a real Whitetail to the right), unlike the two-pronged branching antlers of Bambi and his O. hemionus conspecifics.

Closely related species, yes. But would this bode well for Faline's fawns, should Bambi lose the fight?

In this case, there's more to the species difference than antlers. The two species of deer also have significantly different gaits, evolved in two different habitats for most effective predator avoidance.

In 1992, Susan Lingle of the University of Calgary published her study (Behaviour, 1992; v 122) of the gaits of Mule Deer, White-tailed Deer, and their hybrids. Hybrids are sometimes found in areas of Calgary (and possibly other areas where the two species exist in close proximity) where large predators have been removed by humans.

  • White-tailed Deer, which live primarily in lowlands, GALLOP (a gait like that of a racehorse in full stride) to escape predators. On its habitat's relatively flat substrate, a healthy deer can easily outrun a chasing predator.

  • Mule Deer, which live primarily on hilly terrain, STOT (hop with all four feet touching the ground at the same time) from slope to slope to escape a pursuing predator. No wolf or coyote can keep up with a healthy mule deer stotting mightily across the rough terrain of mountain hillsides, sometimes leaping ravines and small canyons in a single bound.

    But here's the rub...

  • Hybrids between the two species have an awkward, erratic, intermediate gait dubbed the "STOLLOP". It isn't very effective at getting the deer away from predators on either flat land or hillsides. Hybrids can survive only if there are no major predators, since they are relatively easy to catch.

    Lingle has hypothesized that the presence of large predators has helped to maintain the reproductive isolation and habitat segregation between Odocoileus hemionus and Odocoileus virginianus. Hybrid fawns get eaten by coyotes!

    What does this mean for Faline and her suitors?

    Bottom Line: Hybridization could spell trouble, if Faline doesn't exercise her right to behavioral reproductive isolation, and reject Ronno's advances, even if he beats the stuffing out of Bambi.