An online resource based on the award-winning nature guide

Animal Tails

River Otter Tails

3-31-17 otter tail impression2 026From their nose to the tip of their tail, North American River Otters measure three to four feet long. Their tail makes up anywhere from a third to nearly a half of their length. A River Otter’s tail is very thick at its base, packed with muscles, flexible, and tapers to a point. It is used to steer when an otter is swimming slowly, propel the otter when it is swimming at high speed and to help the otter balance when it stands upright on its hind legs. River Otters, known for their powerful swimming, can reach speeds of six to seven miles per hour with the help of this appendage.

When loping through the snow, River Otters often hold their tails up off the surface of the snow, but not always. Occasionally drag marks can be seen.  In the accompanying photograph, an otter had leapt up an incline, and in so doing left an imprint of its impressive tail in the snow.

(Thanks to Alfred Balch for photo op, and Joan Waltermire for her sharp eyes.)

Naturally Curious is supported by donations. If you choose to contribute, you may go to and click on the yellow “donate” button.

Bird Tail Feathers

mystery-photo-img_0672Although the number of tail feathers is quite variable across groups of birds, the most common number is 12. The left and right tail feathers are mirror images of each other. The outermost tail feather is highly asymmetrical (narrow outer vane, broad inner vane). The feathers become more symmetrical toward the center, with the two central tail feathers usually exactly symmetrical (vanes on both sides of the shaft equal in width). There is a similar change in the curvature of the tail feather shafts from outer to central, with the shafts of the outermost tail feathers usually strongly curved, gradually straightening toward the center, with the central tail feathers shafts completely straight.

Groups of birds can have certain tail feather traits in common. For instance, the tail feathers of most waterfowl are short (although the pictured female Hooded Merganser’s are relatively long), while many gamebird tail feathers are used in display and thus are boldly patterned and/or elongated. Woodpecker tail feathers have pointed, stiff tips that the birds use to brace themselves against tree trunks. Even within a group, such as waterfowl, there can be specific tail traits such as the drake Northern Pintail’s long twin tail feathers and the drake Wood Duck’s squared-off tail feathers.

Naturally Curious is supported by donations. If you choose to contribute, you may go to and click on the yellow “donate” button.


Opossums Scrounging

3-19-14 opossum2  021Within the last century the Virginia Opossum has extended its range northeastward and now occurs sporadically throughout most of New England. Its adaptability to a great variety of habitats and its omnivorous diet (is there anything an opossum won’t eat?) have enabled this marsupial to live in much colder climates than it initially inhabited. As long as food can be found,the opossum’s greatest challenge is dealing with New England’s cold winters. Lacking much hair, the ears and tail of an opossum often suffer from frostbite, turning black at the edges (ears) and tip (tail). Look for signs of this nocturnal scavenger under bird feeders – in the winter it can even be seen foraging in the daylight, as the opossum in this photograph was earlier this week. (Thanks to Dotty Cummings for photo op.)

Naturally Curious is supported by donations. If you choose to contribute, you may go to and click on the yellow “donate” button.

A New Book for Budding Naturalists

COVER-BeaversBusyIs there a youngster in your life who might love his or her own book about beavers? My third children’s nature book, The Beavers’ Busy Year, has just been released. Having been an ardent admirer of this rodent for many, many years, it is gratifying to have had a chance to instill a love for beavers in youngsters age 3-8 with this non-fiction book. The adaptations of beavers’ noses, eyes, ears, fur, feet and tails are highlighted in the text and photographs take the reader through the seasons of the year from a beaver’s perspective. Activities at the end of the book engage children in matching photographs of various beaver signs such as tracks, scent mounds and incisor marks with written descriptions. There are also activity/informational sections on beaver tails, beavers as engineers and creators of habitat for other wildlife, and dam building. It should be available at your local bookstore, but if not, I’d greatly appreciate your letting them know about it. Thank you!

Mink Meanderings

2-5-14 mink with tail dragging2 IMG_2152As these wet footprints and tail drag marks indicate, mink are excellent swimmers, and spend a great deal of time in all seasons foraging in and along streams and ponds. As a rule, all weasels can often be found close to water, as they drink often, though relatively little at a time. But mink do far more than drink water – they find much of their prey, including crayfish, frogs and fish, in it and are very well equipped to capture them. Mink can swim underwater to a depth of 18 feet and they can swim as far as 100 yards. Look for their tracks going in and out of openings in the ice that covers much of a stream’s surface this time of year.

Naturally Curious is supported by donations. If you choose to contribute, you may go to and click on the yellow “donate” button.

Beaver Tail Boosts Balance

beaver tail 062A beaver’s tail is a wondrous thing. Beavers steer and propel themselves with it, store fat for the winter in it, regulate their body temperature with it, use it as a prop when sitting or standing and signal alarm with it by slapping it against the water. While these functions are fairly well known, there is another use that is not observed as often. When floating on top of the water, beavers use their tail as a stabilizer, to keep their body upright. As this photograph illustrates, beavers often raise their tail out of the water in order to stabilize themselves.

Naturally Curious is supported by donations. If you choose to contribute, you may go to and click on the yellow “donate” button.