What Otter Is This?

Otters are terribly cute little critters. There are several species worldwide, but in North America we have the river otter and the sea otter. Other than one living in a river and one living in the sea, what are the differences? If you should happen to see an otter near the coast, how do you know which one it is?

It might seem silly to not know what otter you are looking at, but coastal river otters will swim into the ocean. Now that you can’t always rely on the type of water to tell the otters apart, what do you do?

You probably won’t have the two otters side by side for a comparison, but the sea otter is much larger, twice or even three times the size of the river otter. The sea otter’s tail is shorter and flatter, while the river otter’s tail is about half the length of its body. River otters have a more rounded nose than sea otters, and the river otter’s nose farther above the mouth. The sea otter’s nose is slightly pointed at the top and the bottom comes to the mouth much like a cat’s. The sea otter has very dense fur, which is why they were hunted to near extinction. The river otter has a course fur and a layer of fat.

Sea otters at sea (Marine Mammal Commission)

River otter swimming

Movement is a good indicator of which otter you’re looking at. Sea otters swim almost exclusively on their backs, using their bellies as a dinner table. River otters swim on their bellies (riding very low in the water) and usually eat on land. On land, river otters move quite well, running with an arched back or sliding downhill on snow. Sea otters rarely come ashore, and when they do, they are clumsy critters that waddle more than they walk.

Sea otter ashore (Oregon Zoo)

River otter on land (Smithsonian National Zoo)

Hopefully you will be lucky enough to find yourself in a position that you see an otter and wonder what kind it is. Sea otters live exclusively on the West Coast and are a threatened species so you will be lucky indeed to find one. River otters have suffered in the past due to hunting and trapping pressures just as their seafaring cousins, but have had a more successful recovery thus far and enjoy no special federal protection.

So you’re far more likely to see a river otter based on population and range. Still, seeing a river otter is a special event. I’ve come across them in the wild twice, and both times it was an unexpected delight. The first otter was in my pond while I was surveying amphibian egg masses. The second was in Capitol Lake in Olympia, WA where I was joining a group for an evening bat program. Check your local waterways; you may be in for a pleasant surprise too!

This week's otter information comes from the Seattle Aquarium. Don't forget to follow Nature Minute on Facebook!

Species of the Month

February's species of the month is a pink bird, reminiscent of Valentine's Day. The roseate spoonbill is a spectacle to behold with pink plumage that only becomes more vibrant as the bird ages. It's not necessarily known for being a love bird, but at least the color matches the month.

Roseate spoonbill (Cornell Lab of Ornithology)

Scientific name: Ajaia ajaja

Kingdom: Animalia (animals)

Class:   Aves (birds)

Order: Ciconiiformes (storks and relatives)

Range: Gulf Coast south across the Caribbean, Central and South America

Habitat: freshwater and saltwater marshes

Lifespan: 16 years on average

Diet: small fish and crustaceans, plant matter, insects

Predators: alligators, coyotes, hawks (prey on chicks), raccoons (prey on chicks and eggs)

Conservation Status: No special conservation status

Other Information: The roseate spoonbill feeds by swishing its spoon shaped bill in the water. Like flamingos, the pink pigmentation comes from the crustaceans in the spoonbill’s diet. They were hunted for their feathers to near extinction. Protection in the 1940s led to their remarkable comeback. However, they remain vulnerable due to habitat loss.

This month's information comes once again from University of Michigan's Animal Diversity Web, as well as New Hampshire PBS.

(Texas Parks and Wildlife)

(US Fish and Wildlife Service)

Winter Adaptations

As I deal with a pair of winter storms over the course of writing this blog, I am sitting cozy and warm inside my house. How do animals, who don’t live in houses with central heating or furnaces make it through the winter? Some migrate to warmer areas, but those that stay behind have special adaptations that help them cope with the cold and snowy weather.

Many animals go into mega energy conservation mode during the winter because not only do they lack heating systems for their homes, they also lack supermarkets that carry a reliable food source. For herbivores, their plant-based food supply is either dormant (and not producing the nutritious shoots they crave), or buried under snow and ice. Whether warm-blooded or cold-blooded, both need to keep warm to survive. Cold-blooded critters rely on the sun’s radiant heat to stay warm, and this is a challenge when it’s cold outside and the sun isn’t reliable. Warm-blooded critters metabolize food to stay warm- they eat much more than cold-blooded ones. One option to keep up metabolism is to spend energy to search for scarce food. But there are other ways to get by.

Hibernation is probably the first coping mechanism you think of, and it’s quite common in the mammal world. Bears do it, bats do it. What is it, compared to normal sleep? When you go to sleep your body slows down. Breathing and heart rate go down and metabolism slows, and your body temperature cools a bit. Hibernation is an extreme version of this. But to be asleep for weeks or months on end requires quite a bit of sustaining energy, even if bodily functions slow to the point of nearly stopping. That’s why bears go on a feed frenzy each fall, gorging themselves on spawning salmon or high-energy moths if they live in the right place.

NPS graphic of a hibernating bear

For those that don’t hibernate, finding food is a priority. Arctic foxes and snowshoe hares both grow a white coat for snow camouflage. The fox uses its camo to hunt; the hare uses its to avoid being eaten. The bison uses its large head as a snowplow to uncover buried vegetation. Ever wonder what that large hump at its shoulder is? Extra muscles to support all that head.

Snowshoe hare (Montana Fish, Wildlife, and Parks)

Bison plowing for food (NPS)

Preserving body heat is a great way to maximize caloric efficiency. The thick fur coat of a muskox traps body heat. Blubber insulates whales, seals, and walruses. Polar bears have black skin that absorbs heat, and their fur traps heat, including body heat that they radiate.

Walruses (US Fish and Wildlife Service)

Ease of mobility is also an efficiency adaptation. Lynxes and caribou both have large feet that act as snowshoes, making it easier to get around so they burn fewer calories doing so.

Check out the foot on that lynx! (Natural Resources Research Institute)

These are just a few of the many adaptations that make survival possible for warm-blooded mammals. There are others, and there are also adaptations for cold-blooded animals (like a frog with antifreeze in its blood) and plants too! Enjoy your heater for the rest of the winter! 

Nature Minute Book Club

It's February and the days are getting noticeably longer, but we still have quite a few cold weeks ahead of us here in the Northeast. This month is like life in the Stone Ages: nasty, brutish, and short. I have snow coming twice before the Super Bowl is over, and I'm pretty sure more will be along shortly afterwards. Once the big game is over, what else is there to until spring but read? Having said that, feel free to peruse these titles from the Nature Minute book shelf.

Voyage of the Turtle: In Pursuit of Earth’s Last Dinosaur by Carl Safina

Safina travels the globe following sea turtles from their nesting grounds to their feeding grounds and points in between, looking for answers. What’s being done to protect them? What are the negative impacts people have on them, and how can we reduce or turtle-stomping footprint? Just where to they go and what do they do? If nothing else, you’ll learn just how immense these magnificent critters are and how they have adapted to a carefree life adrift and the challenges they face.

The Hidden Life of Trees by Peter Wohlleben 

Wohlleben, a German forester, takes us into the heart of his forest to show us how trees interact with friends and family, other tree species, and the animal world. Fascinating ideas about tree cognition, memory, and communication, as well as trees’ nurturing abilities will change the way you look at plants. Is a forest bigger than the sum of its parts? 

The Sun’s Heartbeat by Bob Berman

This book is the sun’s biography, from its humble birth to its spectacular future death. In between, learn about our changing relationship with the sun over the centuries, how it influences everything, and take a historical trip through own growing sea of knowledge about our nearest star. A seasoned skywatcher, Berman has yet to lose his sense of awe over solar eclipses.

Travels in Alaska by John Muir

America’s leading conservationist of the 19^th century recalls his journeys to Alaska in 1879, 1880, and 1890 in this book, which was still unfinished as the time of his death. Relying on his careful expedition notes, Muir gives a poetic narrative of his voyages exploring mountains and glaciers and documenting the flora and fauna of the Last Frontier while describing the scenery with a sense of reverence and awe. His love of life and the outdoors really shines through.

The Thing With Feathers by Noah Strycker

This book is about birds and people. Not relationships between the two, but common traits that will shock you. In some regards, birds are just as intelligent as humans. Sometimes, understanding their behavior helps us understand human nature. Deep down inside, on some basic level, maybe we’re not above the animals. Language and culture are thought to be defining human traits, but what happens when a “lower” animal develops art?