THE UBIQUITOUS BUNNY
(Page 4 of 7)
When you consider that virtually all North American
predators-from the tiny least weasel to the gargantuan
grizzly bear, plus myriad other hunters both winged and
human-hold the cottontail to be one of the most delectable
items on nature's menu, the continued survival and even
prosperity of the genus is downright amazing. Sure, old
Peter is adept at both running away (at up to 20 miles per)
and hiding from those who would invite him to dinner, but
the real secret of the cottontail's success is its
prolificacy.
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To get the reproductive ball rolling, nature has endowed
cottontails with a randiness rivaling even that of humans.
Second, cottontails attain sexual maturity with astonishing
rapidity (females of one species are capable of breeding
within 80 days of birth). Third, the cottontail's short
gestation (26 to 30 days) allows for the production of from
two to six litters during the annual half-year breeding
season (roughly February through August, peaking in May).
Fourth, cottontail litter size is large, with three to six
kits common and up to eight not unusual.
Thus, a single Madam Cottontail has the potential of
producing some 50 young per year.
And, as if all of that wasn't sufficient to guarantee their
survival, nature has equipped rabbits with some of the
animal kingdom's finest-and least
understood—conceptional shortcuts. Witness: Through
the phenomenon of induced ovulation, rabbit does
release their eggs, not on a fixed timetable, as do most
mammals, but only and always in response to the stimulus of
copulation. This assures that every time a female
cottontail mates, an egg will be in position for
fertilization. A second little-known bunny reproductive aid
is postpartum estrus, wherein female lagomorphs
are capable of conceiving immediately after giving birth,
thus achieving continuous pregnancies. (In fact, in a
remarkable phenomenon known as superfetation, the
females of some species apparently can conceive a second
litter before completing delivery of the first,
thus achieving overlapping pregnancies.)
In addition to reproducing themselves in wholesale lots,
cottontails have an impressive potential longevity for such
small mammals, with many species capable of living as long
as 10 years under benevolent circumstances. In the wild, of
course, this potential is seldom realized; the average life
span for adults is just 15 months, with around 90% of each
season's crop of kits perishing of natural causes
(primarily, disease and inclement weather) or taken by
predators. (Human sport-hunting pressure-or the lack
thereof -seems to alter the death rate only slightly.)
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