Here comes Peter Cottontail, hopping down the bunny trail

In honor of Easter this weekend, this week's post will explore that mammalian reproductive enigma that confuses children across America every spring: the egg-laying Easter Bunny! The origins of this tale (get it? get it?) of an egg-laying mammal are a little fuzzy (double pun! Oh, how I crack myself up!).

The story most likely comes from a German folktale that was introduced to American audiences by immigrants in the 18th century. The German folktale of the "Oschter Haws," a hare that laid nests of brightly colored eggs in children's hats and bonnets every spring, itself has pretty murky origins. The Grimm brothers made a feeble attempt to give the story a little historical credibility by attempting to link it to pre-Christianity pagan myths, but even this was a stretch. Odds are, the story is an amalgamation of historical fertility symbols with new Christian traditions. And, as we are constantly reminded by advertisers every spring, rabbits and Easter are forever intertwined.

What Easter bunny eggs look like when they hatch.

But why are rabbits and hares tied so closely with fertility, and fertility tied with Easter celebrations? Easter coincides with the beginning of spring - the time of rebirth and renewal after the long, dormant, cold winter months. And with that renewal comes lots of new baby animals. Lots and lots of baby animals. And in order to create new baby animals, that means the parent animals had to…well, you know. And what group of animals are known for copulating like bunnies?

Well, I think I just answered my own question.

Rabbits, and hares as well, are members of the Leporidae family. They closely resemble rodents, and used to be classified as such, but are now in their own category thanks to significant differences in skull, jaw, and tooth formation. One of the most famous species of this family is the Eastern Cottontail (Sylvilagus floridanus), found all the way from Canada to South America and as far west as the Great Plains. Suffice to say, it's a pretty common rabbit. And, to put it lightly, these rabbits are "very productive" in the reproductive department.

Eastern cottontails can have anywhere from three to seven litters per year, thanks to a month-long gestation period and two-week weaning period. Each litter can have anywhere from four to seven young. That's anywhere from 12 to nearly 50 babies for one mother per year. Considering that 80% of these litters are born from April to June, it's pretty easy to see where the fertility-rabbit connection came from.

All in a day's work.

Unfortunately for these proud super-rabbit-moms, there's a reason why they need to produce so many offspring. The average mortality rates for eastern cottontail rabbits hover at around 80% per year, most of which happens during the breeding season. Predation by coyotes, bobcats, foxes, owls, and hawks make up the bulk of this mortality. Cottontails tend to prefer early forest successional habitats, meaning areas of dense shrubs and thickets. As they move out into the open from the cover of these thickets during the spring, they are more open to predation.

Don't keep yourself up too late at night worrying about the rabbits going extinct, however. In addition to early succession habitat, many species of rabbits also take advantage of crop fields, orchards, and pastures - prime agricultural land which, coincidentally, provides a pretty easily attainable food source for these herbivorous almost-rodents.

What? I'm totally supposed to be here.

One important question to raise, however, is why rabbits move in to human agricultural fields. Could loss of natural early succession habitat be a factor? It wouldn't be the first case of wild animals relocating to human-influenced areas thanks to loss of natural habitat. Although the rabbits are pretty adept at re-populating themselves, that's not the case for other early succession forest-dwelling critters. Many species of birds (sparrows, songbirds, shrikes and the like) rely on this habitat to build their nests and lay their eggs. Less habitat equals fewer nests, and thus, fewer eggs. Sigh. Now, if only the Easter bunnies really did lay eggs. . .