Architects of The Desert: Jackrabbits and Cottontails | KCET
Architects of The Desert: Jackrabbits and Cottontails
Some desert animals are difficult to identify. I've had to take a second and third look to determine whether a little stripey rodent is a Panamint chipmunk or an antelope ground squirrel, for instance. I had a great conversation on Facebook last week arguing over the identity of the rattlesnake I saw on a hike on San Jacinto on Wednesday, with three species contending for the title. (My herpetologist friends eventually weighed in, and it was a red diamond rattler, now probably asleep again what with the recent snow.) And don't even get me started on thrashers or sparrows or, for that matter, even small birds of prey if I haven't had my coffee yet.
But then there are some desert dwellers that are very easy to identify. Take for example the distantly related mammals Lepus californicus and Sylvilagus auduboni. Both are inconspicuously colored. Both spend most of their time hiding. But even a toddler can identify them instantly, to a reasonable first approximation, and likely at the top of her lungs: "Bunny!"
The two species mentioned aren't the only bunnies to be found in the California desert. The very widespread snowshoe hare (Lepus americanus) is recorded from the northern desert in California, living in the sagebrush grassland of the Great Basin desert. The related white-tailed jackrabbit (Lepus townsendii) mainly lives in the mountains on the east side of the Sierra and Cascades, but ventures out into the desert steppe of the Modoc Plateau in the extreme northeast of the state.
In that same portion of the deserts lives what might be the California mammal with the highest concentration of squee per ounce of body weight: the pygmy rabbit, Brachylagus idahoensis. It's the world's smallest rabbit species, with most individuals weighing in at less than a pound. Farther south, the mountain cottontail, Sylvilagus nuttalli, whose range extends from the Great Basin desert to the northernmost edge of the Mojave, is notable for being an avid tree-climber. If you're hiking in the forested hills around Bishop and you see long ears and a fluffy white tail on a branch five feet above your head, that's a mountain cottontail.
In the Southern California deserts, though, any wild bunny you see is one of the two species I mentioned first: Lepus californicus, the black-tailed jackrabbit, or Sylvilagus audubonii, the desert (or Audubon's) cottontail. It's easy to tell the two apart. If you see a bunny in the Southern California desert, ask yourself if you'd call it "lanky." If so, that's a jackrabbit. If not, it's a cottontail. Cottontails are compact and pudgy looking. Jackrabbits are neither of those things. Jackrabbits' frames might put one in mind of the young Abraham Lincoln, whereas desert cottontails... I don't know. Maybe Bill Clinton. Only fluffier.
I use the word "bunny" rather than "rabbit" to describe the two partly because it's fun and partly because technically speaking, and despite their common name, jackrabbits aren't rabbits. They're hares. Hares are related to rabbits, but their young are born fully furred and with their eyes open, while baby rabbits spend some time in the helpless "pinky" stage before growing fur and opening their eyes. Rabbits nest in subterranean burrows, while hares simply make a depression in the ground in which to bear their young.
A moment's thought will reveal how those pairs of traits make sense together. Young born out in the open benefit greatly from insulation and the ability to see predators, while rabbits who have their babies in a protected burrow save wear and tear on the mother by letting the kits do some of their developing outside the womb.
Black-tailed jackrabbits and cottontails both breed year-round, if there's sufficient food, with up to half a dozen babies -- called "leverets" in the case of the jackrabbits -- per litter. If food is scarce, cottontails will stop breeding in summer and fall. Both eat just about anything vegetable: grasses, herbs, cactus pads, leaves from shrubs, yucca shoots, crop plants. A month after 2005's devastating Hackberry Fire in Mojave National Preserve I wandered into the edges of the burned area to see the damage for myself; the only animals in evidence were brazen black-tailed jackrabbits feasting on new sprouts of banana yucca that had come up post-fire.
A jackrabbit is almost a caricature of a rabbit: ungainly rear legs, outlandishly long ears, angular and eccentric. They're more likely to be out during the day than their distant cottontail cousins: their ectomorphic body plan allows them to shed heat rapidly, and those ridiculous ears act as an efficient blood cooling system.
Desert cottontails are rounder and shed heat less easily, and not coincidentally they tend to be less active during the day than jackrabbits. Their habit is what naturalists refer to as "crepuscular": most active at dawn and dusk, but then hunkering during the heat of day, and at night when the coyotes are abroad. A cottontail will rest during the day, but that doesn't mean it's sleeping that whole time. Protected from the worst of the sun beneath a copse of blackbrush or other bristly shrub, a cottontail will spend the day snacking, scratching and snoozing. Walk through a stand of blackbrush at high noon and you will likely spook a cottontail or three, who will take off in a classic rabbit zig-zag predator avoidance mode, leaving behind abundant evidence of snacks past.
That evidence might be the most important contribution rabbits and hares make to the desert environment, aside from the service they provide by transforming leaves into coyote and hawk food. Plant nutrients in the desert are few and far between. The lucky plant a rabbit or hare uses as shelter may give up a few leaves to questing teeth, but in return it gains a supply of manure and nitrogen collected from the surrounding acre and concentrated in conveniently available form.
The desert doesn't repay this kindness too generously. A desert bunny's lifespan is pitifully short, on average. I have a pet rabbit (of the European species, Oryctolagus cuniculus) now winding down to the end of his life -- probably this week, sadly -- at the advanced age of 11 or 12. Wild rabbits are lucky if they reach a quarter that age. Rabbits and hares compensate for that by breeding prolifically, gambling that at least one or two progeny from their many litters will survive to reproductive maturity. In a healthy desert ecosystem, coyotes and foxes and owls and snakes will cull the surplus bunny population and keep things more or less in balance. Cut out the predators and the rabbits will starve to death instead, taking the plant life with them.
And yet there's something more to rabbits and hares than mere fluffy processors of vegetation, simple coyote snacks on the hoof. Having gotten to know a European rabbit pretty closely over the last decade, I've come to see reflections of his surprising ferocity in his desert cousins, and of their sudden, unexpected trust. Some years back I took a walk at sunset in the Mojave Preserve and spooked about eight desert cottontails who'd been nibbling new spring greens in a clearing. One hesitated in its flight, waiting at the edge of the shrubs. I sat down on the ground to watch her. She regarded me for a time, then came to within fifteen feet of me and settled in. We sat there together for twenty minutes as the sky turned violet and the sun dropped down behind Halloran Peak.
This piece is dedicated to my friend Thistle, whom I will miss.
Chris Clarke is an environmental writer of two decades standing. Author of Walking With Zeke, he writes from Palm Springs regularly at his acclaimed blog Coyote Crossing and comments on desert issues on KCET weekly. Read his recent posts here.
For ongoing environmental coverage in March 2017 and afterward, please visit our show Earth Focus, or browse Redefine for historic material.
KCET's award-winning environment news project Redefine ran from July 2012 through February 2017.
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