rabbits | Nantucket, MA
Island Science

Rabbit, Rabbit, Rabbit

by Dr. Sarah D. Oktay, Managing Director UMass Boston Nantucket Field Station

Eastern CottontailThis week’s title comes from the British tradition adopted in New England to say “rabbit” or “rabbits” several times in succession or “white rabbit” upon first waking on the first day of the month in order to have good luck all month. One of my favorite people on island (Lauren at the Toy Boat) asked me to tell her more about Nantucket bunnies this past week, which was perfect timing on her part as I wanted to write about the abundant population this summer. I’ve written about Nantucket rabbits before, but there is new research going on in a search for native rabbits and they are such an iconic part of summertime life here that I thought round two would be in order. You might recall that I first wrote about rabbit/bunnies/hares when our dog Jake found an underground nest of baby bunnies. The nest was concealed under a layer of grass forming a lid to the nursery cavity, which was simply a shallow dug-out indentation in the soil.  Both lid and nest were lined with fur and when the top was moved aside, the furry baby bunnies (known as kits or kittens) would start hopping in reaction to the exposure.  The terms cozy and cute don’t begin to describe it.

So Lauren’s first question was: what is the difference between a rabbit, a hare, and a bunny? This is a very good question, especially if you go down the rabbit hole of etymology (word origins). The short answer is that both rabbits and bunnies refer to the same animal and their use has been intertwined for hundreds of years. But hares and rabbits are two different things. Hares and rabbits are both in the family Leporidae (didn’t know Tim had his own family did you?), but there are enough differences between the two to put them in separate genera (plural of genus). Rabbits are in eight different genera, today we’ll be talking about one, Sylvilagus with 13 species. Hares and jackrabbits belong to the genus Lepus. Both animals have long ears, powerful back legs and a divided upper lip (where we also get the term hare-lipped). Hares are generally larger than rabbits, with longer ears, and black markings on their fur. They also do not burrow, but make nests in the grass. Because of their exposed nesting sites, hares are precocial (in biology precocial refers to mature and mobile offspring) when born which means they have fur and their eyes are open. Rabbits, on the other hand, are born naked, blind and helpless (the term for this is altricial), so they live in more secure dens underground. The cottontail rabbit tends to blur these lines by being a rabbit but living right at ground level essentially in a relatively exposed nest.  Confused yet? Me too. Rabbits have been domesticated to be pets, while hares have not been domesticated.

The word hare comes not from “hair”, their soft coat of dull-colored fur, but possibly from the West Germanic word khasan or Dutch hase, meaning “gray.” Rabbits were originally called coneys based on the French from Anglo-French conis, plural of conil “long-eared rabbit” (c.1200) shortened from the Latin cuniculus (source of Spanish conejo, Portuguese coelho, Italian coneglio) or based on the Irish word ‘coinín’ depending on who you ask. “Rabbit” first referred to the young of coneys (and was apparently in use as early as the 14th century) until eventually the word took over in popularity. Incidentally, this is also the origin of the name Coney Island or Rabbit Island, the beachside amusement park in New York. It is one of the only references to coney that is still used in North America. Read more at http://hotword.dictionary.com/rabbit-bunny-hare/#8rxWZjibuj4wETRx.99 accessed July 15th 2013. Believe it or not the origins of the word rabbit and coney and how they made their way through language is extremely involved. Read more at the Online Etymology Dictionary (http://www.etymonline.com/index.php?search=coney). The first known rabbits originated in Spain, a country the Phoenicians called “land of the rabbit,” but it was not long before they spread to the rest of Europe, then throughout the world. Although many native rabbit species in the U.S. are actually hares, the early colonists, for some unknown reason, dropped the word hare out of their vocabulary, and it is rarely heard in American speech to this day [1921, H.L. Mencken, “The American Language”].

So what about the word “bunny”? Why do we call rabbits bunnies? The word comes from the 1680’s, diminutive of the Scottish word “bun” which was a pet name for “rabbit,” previously used in the 1580’s for “squirrel,” and also used as a term of endearment for a young attractive woman or child (c.1600). Ultimately it could be from Scottish bun “tail of a hare” (1530’s), or from French bon, or from a Scandinavian source (http://www.etymonline.com/index.php?search=bunny) or from Mars for all we know at this point. So we call them bunnies because they are cute and a bunny is a cuter word. There is no difference between the two. A good way to differentiate the words is you own a pet bunny, you eat rabbit. Capiche?

So what do we see running all over the island? We are looking at the Eastern Cottontail (Sylvilagus floridanus, J.A. Allen, 1890) which is a New World cottontail rabbit, a member of the family Leporidae.  It is one of the most common rabbit species in North America. It is native to many states in America, but not to New England and as an introduced species, it has pushed out its brethren, the New England Cottontail.  Like many other creatures found on Nantucket, rabbits were brought to Nantucket for hunting reasons.  In fact, Eastern Cottontails were first introduced to New England on Nantucket in the 1880s. We’ll discuss below the consequences of the seemingly innocuous introduction.

The genus name “Sylvilagus” is from the Latin word sylva (forest) and the Greek word lagos (hare), and the species name “floridanus” refers to the state in which they are considered endemic (common and native).  The taxonomic ranks of the eastern cottontail show us they belong to the Phylum, Chordata (has a spinal cord); Class, Mammalia (usually but not always live birth, mammary glands, neocortex brain); Order, Lagomorpha; and Family, Leporidae.  The name “leporid” is derived from Latin leporis, which is a possessive case derivative of the word “lepus” or “hare.”  Rabbits vary from rodents, so they were grouped into their own Order, Lagomorpha (Greek for “hare form”). The members of Lagomorpha (rabbits, hares, and pikas) have an extra set of incisors (teeth) in their upper jaw, are strictly herbivores (plant eaters) and have a few other physiological (body related) differences.  Like rodents, their teeth keep growing so they have to gnaw constantly to keep them from getting too long.  There are 35 recognized subspecies of Sylvilagus floridanus scattered throughout the Americas (most in Mexico) (http://www.fs.fed.us/database/feis/animals/mammal/syfl/all.html).

The Eastern Cottontail has large hind feet, long ears, and a short fluffy white tail. They typically have speckled brown-gray fur on their backs and sides, reddish-brown fur around their neck and shoulders and much lighter fur around their nose and abdomen.  They are distinguished too by their large eyes and, of course, the white coloring on their “cottontails.”  In the winter, their fur may be more gray than brown. The kittens develop the same coloring after a few weeks, but they also have a white blaze that goes down their forehead that eventually disappears as they get older. The average adult weighs about 2-4 pounds; however the female tends to be heavier. The females here at the Field Station look like tanks. Once a rabbit has its adult coat, it loses its fur twice a year in molting. Although the exact schedule depends on climate, most rabbits molt in spring and fall. Molting begins at the head and proceeds back. When a rabbit is pregnant, the fur on her belly, thighs and chest loosen, so that they can be easily removed to fill out the nest.

The Eastern Cottontail can be found in meadows and shrubby areas in the eastern and south-central United States, southern Canada, eastern Mexico, Central America, and northernmost South America. It is abundant in Midwest North America, and has been found in New Mexico and Arizona. Its range expanded north as forests were cleared by settlers. Originally, it was not found in New England, but it has been introduced here and now competes for habitat with the native New England Cottontail. The New England cottontail (Sylvilagus transitionalis), is very similar to the Eastern Cottontail, except that it has a black patch between its ears and a different skull shape, among other less noticeable differences.

The Eastern Cottontail eats a variety of different plants including grasses, clover, fruits, and vegetables. About half the cottontail’s intake is grasses, including bluegrass and wild rye. In the winter it eats the woody parts of plants like the twigs and the bark of brambles, birch, oak, sumac, dogwood, and maple trees. The cottontail prefers an area where it can hide quickly but be out in the open in grasslands to feed. Cottontails are happy in thickets, meadows, and edge environments between woody vegetation and open land. Its range of habitats includes areas with second growth shrubs, vines and low deciduous trees. Eastern cottontails are crepuscular (twilight) to nocturnal feeders; although they usually spend most of the daylight hours resting in shallow depressions under vegetative cover or other shelter; they can be seen at any time of day.  Eastern cottontails are most active when visibility is limited, such as rainy or foggy nights. Eastern cottontails usually move only short distances, and they may remain sitting very still for up to 15 minutes at a time (US Fish and Wildlife at http://www.fs.fed.us/database/feis/animals/mammal/syfl/all.html).

A great website called www.bookrags.com has a excellent summary about rabbits of all kinds including our Eastern Cottontail and I learned some interesting facts there such as the fact the rabbits are “hind gut” digesters which means that portions of the digestion system following the stomach (small and large intestine and large cecum) are where all the action happens. Much of a rabbit’s diet is composed of large amounts of cellulose, which is always in plants and can be hard to digest. Rabbits solve this problem by passing two distinctive types of feces or poop: hard droppings and soft black viscous pellets, the latter of which are immediately eaten (Yum! Some dogs cannot resist this). Rabbits reingest their own droppings (rather than chewing the cud as do cows and many other herbivores) in order to fully digest their food and extract sufficient nutrients. So yes, rabbits eat their own poop, a behavior called coprophagy. And if that is not gross enough for you, here is another fun fact: rabbits are incapable of vomiting due to the physiology of their digestive system. I bet you’ll never forget that trivia! Dogs tend to eat rabbit poop because they are craving digestive enzymes and extra nutrients and the poop is a good way to get them.

Back to more appetizing matters. A cottontail’s sharp senses of hearing and smell are among its adaptations for survival. The eyes are located on the sides of the head for wide peripheral vision. The ears are large and pivotal and are cupped to detect faint sounds. Cottontails are rarely found out of their burrows looking for food on windy days. This phenomenon is due to the fact that the wind interferes with their hearing capabilities. Hearing an oncoming predator approaching is their primary defense mechanism. The cottontail sometimes checks the surroundings by standing on its hind legs with its forepaws tucked next to its chest. When danger is sensed, the cottontail “freezes” and relies on camouflaged coloration to avoid detection. They are essentially silent, sometimes uttering quiet grunts and purrs or using their hind legs to thump the ground to communicate although when caught by a predator, they can produce a bloodcurdling scream. Another survival mechanism is “flushing” or basically, “running like the wind.”  If necessary, cottontails can move quickly (18-20 mph) for short distances. Their zigzag running pattern is meant to confuse predators. They mainly drive me crazy as they dart back and forth over and over again while I am driving down my dirt road.  Eastern cottontail rabbits do not hibernate in the winter and instead find hollows to snuggle in and stay warm.  They are also very nocturnal as any night time drive on the island will verify. Last but not least, the males can be very territorial and may occupy as many as 5-8 acres while driving off any other males trying to enter their territory. Like deer, male rabbits are called bucks, and females are called does. During mating season, males often fight with each other. The male and female also perform a kind of mating “dance.” The male will chase the female. Eventually the female will stop and face the male and box at him with her front paws. At some point, one of them will leap straight up in the air and then the other one will jump up in the air too. This is pretty funny behavior when you see it firsthand.

As we said above, cottontails are born with very little fur and their eyes sealed shut. As they grow, their eyes open and their ears perk up.  Once their eyes open, a young cottontail is capable of eating solid foods on its own, but will ordinarily remain with its mother and siblings for a short time. Young cottontails are very nervous and may even die of fright if they are handled by a human or caught by a cat or dog.  After the female has given birth to her offspring, she can mate again immediately, so she is off to do what we expect most bunnies to do.  She will come back to the nest to feed the young twice a day for the first three weeks, usually at dawn and dusk; she will not visit the nest in the daytime in order to avoid alerting predators to its location.  As she is practically an absentee mother, her milk is one of the most nutritious of all mammals. The female gives birth about a month after mating. She can have from one to nine babies, although she usually will have four to five young. The babies are weaned after about three weeks and leave the nest after about seven weeks. Females can have three or four litters a year. Eastern cottontails are ready to mate when they are three months old. Their lifespan is on average three years although they can live much longer in captivity. By now you may understand why we see so many bunnies on island. This past winter seems to have been more difficult for their predators and less so for them, with plenty of rain for vegetation and therefore, their population is robust.

The high birth rates and frequent mating of rabbits coupled with their short life span and bottom of the totem pole trophic status results in an 80-85% mortality rate.  This high mortality rate is one of nature’s checks and balances as one pair of rabbits and their offspring could potentially produce five million young over a five-year period. Many mortality factors affect rabbit populations. Weather is a major factor in nest mortality as ground nests are susceptible to flooding in heavy rains. Rabbits are known as the “protein base” for the mammalian food chain and serves as lunch for raptors such as red tailed hawks, coyotes, and many other mammals, not the least of which is humans. The Eastern Cottontail is the most commonly hunted game animal in the United States.

Populations of Eastern Cottontail and the New England Cottontail have varied across the country and through the years as a result of changes in land type. As the Midwest started to build big farms with just a few crops, the Eastern Cottontail populations dropped precipitously while in New England, farms could not compete well with the Midwest farms and therefore some farming land returned to forest sooner, providing a suitable habitat and enough diversity in grasslands for Eastern Cottontails to proliferate (from Wild Mammals of North America by George A. Feldhamer, Bruce Carlyle Thompson, Joseph A. Chapman, 2nd ed, 2003).  The Eastern Cottontail’s ability to spread throughout most of the U.S. lies in its adaptation to many habitats; in the Northeast it tends to favor disturbed and early successional forests with dense understories, lots of forage and cover, and relatively immature trees. As a result, the New England Cottontail has been losing the habitat war with the Eastern Cottontail. For those of you losing the war on keeping rabbits out of your garden, check out this site http://icwdm.org/handbook/mammals/CottontailRabbits.asp for tips on building barriers that work.

This MA Division of Fisheries & Wildlife site: www.mass.gov/dfwele/dfw/wildlife/living/living_with_cottontails.htm, describes the plight of the New England Cottontail and its status as an endangered native rabbit in New England. In New Hampshire and Maine, wildlife officials are attempting to restore some of the habitat favored by the severely deplete New England cottontail population. Mass Wildlife has lots of useful information including estimates of species distribution around Massachusetts, and they list the Black-tailed Jackrabbit or Lepus californicus as still found on Nantucket Island, although they have a caveat that it may be extirpated. The state listing indicates that snowshoe hares (also an introduced species by hunters) may also be lurking around (and that has been confirmed), and they believe that the New England Cottontail has become wiped out on Nantucket and Martha’s Vineyard. Locally the Nantucket Conservation Foundation (NCF) has been assisting the U.S. Fish and Wildlife Service (USFWS) in trapping and testing rabbits on island and looking for the elusive New England Cottontail. The last recorded incidence of a New England Cottontail on Nantucket was a hunter’s specimen received by the Massachusetts Division of Fisheries and Wildlife (Mass Wildlife) in the late 1990’s, but no systematic inventories have been conducted. Nantucket is a likely place to find New England cottontails if they still exist because they use to live here and have plenty of suitable habitat. Karen Beattie (Manager of Science & Stewardship at NCF) and Danielle O’Dell (NCF research technician and field supervisor) were trained by USFWS biologists to conduct trapping and tissue sampling and they have been doing that this past winter on various NCF properties including the field station. Read all about their research and results (so far none found) in their excellent blog at http://ncfscience.wordpress.com/2013/02/08/searching-for-a-certain-some-bunny/.

The occurrence of tick borne disease and its association with our the rabbit population has been known for many decades. According to D.L. Belding and B. Merrill’s 1941 paper in the New England Journal of Medicine (224:1085-1087), “Tularemia in imported rabbits in Massachusetts,” the sudden appearance of tularemia in the Cape Cod region was associated with the importation of 29,689 rabbits from 1937 to 1940 by various Massachusetts game clubs.  Three hundred and forty of these rabbits were released on Nantucket Island.  And as mentioned above, Nantucket got the first wave of imported rabbits back in the 1880s.  So when we imported these rabbits we also imported any nasty bacterium or parasites they may have been carrying.  Tularemia or “Rabbit Fever” was once known as “rabbit skinner’s disease” since persons would skin rabbits infected with this bacteria and become infected through tiny lacerations in their skin.  For many decades extensive research has been conducted on the role the Eastern Cottontail plays in the spread of tularemia, European human babesiosis, and human granulocytic ehrlichiosis (HGE) on Nantucket.  A Google search will bring up a variety of papers from the extensive work of Harvard Public health researchers such as A. Spielman, Sam Telford, and Heidi Goethert.

Rabbits have been shown to harbor a suite of zoonotic organisms (those that can transmit infectious diseases from animals to humans and vice versa), including a Babesia species (Babesia divergens), Anaplasma bovis (agent of bovine-infecting Ehrlichia), and Anaplasma phagocytophilum (the agent of agent of human granulocytic ehrlichiosis). The rabbits often serve as a dead-end host, transmitting diseases to ticks that bite them without getting the disease or suffering ill effects. The vectors and transmission probabilities, successes, and failures between white footed mice, deer ticks, rabbits, dogs, birds, humans, deer, and other hosts is quite complex for each disease. We may explore this in depth in another column, but suffice it to say, when in doubt, be careful when removing dead rabbits on your property.

Parts of this article were previously published in the June 3rd 2009 Yesterday’s Island article which can be found at http://www.yesterdaysisland.com/archives/science/4.php