Small Mammals 101

One of the great things about working at a nature center is access to The Morgue, which most nature centers have. The VIC is not technically a “nature center,” so sadly we don’t have a morgue, but fortunately for us, the folks next door at the Adirondack Ecological Center (SUNY ESF – Huntington Wildlife Forest) have a great collection and we get to access it. So this morning I zipped over and snagged some photos to help illustrate the vole vs mouse vs mole discussion from Monday.

Here we have your typical mouse: Peromyscus spp. The Deer Mouse (P. maniculatus) and the White-footed Mouse (P. leucopus) are very similar to each other and difficult to tell apart. This one was not identified down to species, but looking at that tail, I'm leaning towards deer mouse. To tell the difference, here is the list of things to look for, according to D.A. Saunder’s book Adirondack Mammals:

* The deer mouse’s fur is very soft and luxuriant, which the white-footed mouse’s is not.
* Deer mouse fur tends towards grey on the upper parts, uniform in color or possibly with a faint darker stripe down the middle; white-footed mouse fur tends to be more of a reddish- or orangish-brown, not grey, with a dark strip along the middle of the back from head to tail.
* The deer mouse’s tail is dark above and white below (bicolored), is longer than the combined length of the animal’s head and body, and has a tuft of white hairs at the tip; the white-footed mouse’s tail is shorter than the head and body length, is pale below but not white, and does not have a white, tufted tip.

Note the large ears, as well as large eyes (or, in this case, eye holes). We’ll leave the jumping mice for another day.

Compare with this vole. This is the Meadow Vole (Microtus pennsylvanicus). Voles have large heads, compact bodies, short noses, small ears (“microtus” means small ear), short tail, and smallish eyes.

Here we have a Red-backed Vole (Myodes gapperi); note the color of the fur, compared to the meadow vole. The Adirondack region is also home to the Rock Vole (Microtus chrontorrhinus), and the Woodland Vole (Microtus pinetorum). I don’t have photos of these.

Moving on to moles, this is a specimen of the Hairy-tailed Mole (Parascalops breweri). Things that stand out about moles are the tiny tiny eyes that are covered with fur, no external ear flaps, fur that goes no particular direction (this is a great adaptation for an animal that is scooting around underground all the time – no bad hair days), short legs, and especially the spade-like feet.

The Adirondacks are indeed home to Star-nosed Moles, (Condylura cristata), which are noted for the eleven “tentacles” that sprout from the tip of the nose. These tentacles are believed to detect vibrations or electrical signals of prey under ground or under water. Yes – the star-nosed mole is a very capable swimmer and over 75% of its food comes from an aquatic source. Sadly, I didn’t find a specimen of this creature at the AEC, but if you ever have the chance to see one, it is a must.

Then there are the shrews, which are not rodents. Shrews are in a category all their own: insectivora. The most common shrew is this fellow here – the Short-tailed Shrew (Blarina brevicauda):
Blarina is a hefty shrew (most shrews tend to be fairly small), most noted for its venomous saliva. Yes, Blarina is a deadly predator, which actively hunts other small mammals, even those larger than itself, savagely biting them and “injecting” them with its toxic spit, which is a neurotoxin that shortly paralyzes the food item, enabling this small predator to haul it off without a struggle. According to D.A. Saunders, this shrew’s poison gland contain enough toxin to do in about 200 mice. This is a serious predator.

In the Adirondacks one can also find Water Shrews (Sorex palustris):

Masked Shrews (Sorex cinereus), Smoky Shrews (Sorex fumeus), Long-tailed or Rock Shrews (Sorex dispar), and Pygmy Shrews (Sorex hoyi). I’ll try to get photos of these fellows at a later date and do a blog on shrews. Note that all shrews have the long pointy snouts – a good clue to look for.

So, return another day for Small Mammals 102!!!