Species of the Month

The elk rut is upon us, so to that end the Species of the Month for September is the elk. In North America there are four surviving subspecies and two that are extinct. In Eurasia, where it is known as red deer, there are eight subspecies. 

Female elk herd

Scientific name: Cervus elaphus

Kingdom: Animalia (animals) 

Class: Mammalia (mammals) 

Order: Artiodactyla (even-toed ungulates)

Bull elk

Range: Western North America, northern Europe, northern Asia, isolated reintroduced populations in eastern US, introduced populations in Ireland, Argentina, Australia, New Zealand, and Chile

Habitat: Open woodlands

Lifespan: Average 20 years, but difficult to gauge due to hunting

Diet: Grasses, sedges, forbs; woody growth in winter

Predators: Gray wolves, coyotes, mountain lions, bears

Conservation Status: No special protection 

Elk calf nursing

Other Information: The elk is known for the haunting bugle call of the male during the rut. Bugling is used for attracting a mate and advertising territory. Like other horned or antlered mammals, male elk will spar to establish dominance. Dominant males form a harem of females. On occasion, a lesser male will sneak in to mate with one or more of the harem. Elk are social and form segregated herds. Females and calves are dominated by a single alpha female. Males form a bachelor herd. The sexes mingle during the late summer/early fall migration and mating season. Following the birth of calves, mothers and their babies form a separate nursery herd away from the rest of their normal herd. Aside from being larger than deer, elk can also be distinguished by a larger head, dark mane, and large white rump patch. Like deer, elk are most active in early morning and late evening. Coming around a bend on the way to work and seeing the big white butt in the road is a great way to start the day, if given enough stopping distance. Elk browse on grasses and forbs in spring, summer, and fall. Their winter diet may include green woody growth. As ungulates, they have a multi-chambered stomach and chew their cud. Only male elk grow antlers, which they shed annually. Eastern populations of elk were extirpated in the 19th century. Several successful reintroductions of Rocky Mountain elk have since occurred, notably in Elk County, Pennsylvania, and Kentucky.

Bull elk showing off his rump patch

This week's information comes from University of Michigan's Animal Diversity Web. Stay tuned for a recap of the 2020 firefly season next week.

Hard Working Animals

Police dogs, draft horses, barn cats, and lab rats are all animals that could be considered to work a full time job. In a salute to Labor Day, here are a few wild animals that work just as hard as humans and domestic animals.

Earthworms are working hard to keep your garden healthy. Often overlooked because they remain unseen, these slimy little guys are tunneling all day, allowing air and water to move around the soil. They cycle nutrients by eating decaying plant matter, creating fertilizer that living plants can use. 

Earthworm (Christian Science Monitor)

Mound building termites built mud homes that can reach heights of 17 feet and displace a quarter ton of soil. It can take years to build, and a single heavy rainstorm can damage or destroy it. Worker termites are always on the ready to make repairs as needed. Additionally, they also farm a fungus as a digestive aid. The fungus breaks down partially digested cellulose from the wood and grass the termites had eaten. After the fungus does its thing, the termites re-ingest what the fungus broke down.

Termite mound (Journal of Experimental Biology)

Beavers are the best known engineers in the animal world. They build water tight dams out of sticks and mud. Ponds form behind the dam, and while the beavers selfishly build dams and create ponds for themselves, the important wetland habitat benefits many other species as well. Even humans benefit, as the wetlands filter water and serve as flood control.

Beaver preening

Beaver dam

While you're enjoying a long weekend, just remember the critters that work hard 365 days a year just to survive. This week's information comes from National Geographic for worms and termites.

Species of the Month

Introduction: World Elephant Day is next week, so to celebrate we’re profiling one of the world’s three

elephant species. In addition to the Asian elephant, did you know there are two different African

elephants? There’s the forest elephant and the more commonly known bush elephant, the August

Species of the Month.

African bush elephant (Wikipedia)

 

Scientific name: Loxodonta africana

Kingdom: Animalia (animals)

Class: Mammalia (mammals)

Order: Proboscidea (elephants)

Range: Central and southern Africa

Habitat: Savannah, forest, deserts

Lifespan: 60-70 years

Diet: Grasses, herbs, fruit, tree leaves, and tree twigs, roots, and bark

Predators: Lions, African wild dogs, hyenas, crocodiles, humans

Mother and calf (Wikimedia Commons)

Conservation Status: Elephants are listed as vulnerable on the IUCN red list. They are threatened under

the US Endangered Species Act.

Other Information: The African bush elephant is the largest land mammal in the world. An adult male

can weigh over six tons with a shoulder height of ten feet. Adult males live alone or in small groups,

while females and calves will form a larger herd led by a matriarch. Calves are raised communally

and are totally dependent on maternal care for several months. They reach full independence around

eight years old. Elephants don’t grow their tusks until after they’re a year old and the baby teeth fall

out. They also have a conveyor belt of six molars that wear out and fall out, allowing the next in line

to move forward. After losing the last molars, they can no longer eat properly. The large ears are great

for hearing, but also dissipate heat. Elephants are very mobile with a large range because of the

massive amount of food they need to eat. They can drink up to 50 gallons of water a day. Mud and

dust baths help them keep cool. Predators mainly go after small calves that fall behind the rest of the

herd. The greatest challenges facing elephants are caused by humans. Development has caused habitat

loss, and keep in mind these giants need a lot of room to roam. Poaching is also a serious threat. Most

elephants are confined to protected areas, limiting their population sizes. However, even at a protected

reserve elephants aren’t safe from poachers.

Young elephants at the watering hole (Sierra Club)

This week’s information comes from Animal Diversity Web.

Species of the Month

Introduction: Summer is road trip season, and many people do a road trip through any of
the western national parks. Most folks have a goal of seeing some wildlife, and one of the
iconic animals of the west is the bighorn sheep. They can be seen picking their way along
sheer cliffs in an amazing feat of agility, but I think more people are impressed by rams
crashing into each other head first as they battle for mating rights.

Scientific name: Ovis canadensis

Kingdom: Animalia (animals)

Bighorn ewe enjoying the view

Class: Mammalia (mammals)

Order: Artiodactyla (even-toed ungulates)

Range: Southern Canada south to Mexico, as far east as Texas

Habitat: Mountain meadows, rocky cliffs, deserts

Bighorn rams

Lifespan: 6-15 years, depending on population status

Diet: Grasses, sedges, forbs

Predators: Mountain lions, wolves, coyotes, bears, lynx

Conservation Status: California bighorn sheep subspecies is listed as endangered.

Bighorn lamb taking a break from frolicking

Other Information: There are three subspecies of bighorn sheep: Rocky Mountain, the most numerous
and widespread; California, which is endangered and can be found in the Sierras; and desert bighorn,
which live in the deserts of the US Southwest and Mexico.

Bighorns use rocky slopes and cliffs to avoid and evade predators. Specially built toes allow them to
navigate along ledges that are only inches wide, and excellent depth perception allows them to
accurately leap from one to another.

Bighorns have a shorter lifespan in dynamic populations with a high birth rate, on average 6 or 7 years.
Those in a more stable population with a lower birth rate tend to live longer, to longer than 10 years.

Ewes lounging at the top of a slope

Bighorns live in segregated herds, males in a smaller herd, while females and lambs (male and female)
form larger herds. The herds mingle during the rut, which takes place in fall and early winter. Lambing
occurs in spring, and newborns are able to keep pace with mom almost immediately.

Sparring for mating rights involves males ramming head first into each other at speeds of up to 20
miles per hour. Horns can weigh up to 30 pounds. The force generated is enough to kill a human. Ram
skulls are made of several plates, like human skulls, but the rams' do not fuse into a single solid piece
of bone. That design lets the plates shift to absorb the shock of the repeated blows. The curl of the
horns might also deflect some of the shock away from the head, while a large tendon connecting the
head and neck helps the head recoil.

Rams battling for a mate (Smithsonian)

This week's information comes from University of Michigan's Animal Diversity Web and
Indiana Public Media. Next week wraps up the energy series with a look at the elephant in the room,
nuclear.

Getaway Islands

Summer is here and for many people it's the perfect time to relax at the beach. If you're at an East Coast beach, odds are you're on a barrier island. The Atlantic barrier islands extend from Canada to Florida, then up Florida's Gulf Coast and all the way around to Mexico. Prior to development, many of these islands came and went at the whims of the tides and storms. Now that we've built homes and resorts on them, there is a vested interest to make them more permanent by using jetties to block the outflow of sand and beach replenishment to restore what's been lost. Let's take a look at the natural history of where you built that sand castle.

Grassy dune in New Jersey

Barrier islands, if left to nature, live and die by the tides. Ocean currents carry sand away from the islands. The sand either moves out to the sea floor, where it can be brought back to the island by currents, or it is carried to another part of the island or to a different island. Strong storms can accelerate the process, wiping islands off the map or opening up a new inlet to the back bay.

Hurricane Irene cut these inlets across Hatteras Island (NOAA) 

Barrier islands can move toward the mainland as wind blows sand over the dunes to the bay side. The marshes fill in with sand and build up new dunes, while ocean moves to where the dunes originally were and new marshes form in the bay on the edge of the old marshes.

Salt marsh at Assateague Island (NPS)

The islands are important because they are barriers protecting the mainland from such storms. A few weeks ago we looked at hurricanes on this blog. Barrier islands absorb the brunt of the storm surge that comes in ahead of the hurricane. Developed barrier islands still absorb the storm surge, but not as well as undeveloped islands from times past. Impermeable surfaces like roads and parking are terrible at absorbing water, while sand drains quickly. If the dunes have been removed from an island, the storm surge rushes right over top with nothing but buildings to slow it down.
Barrier islands are also important as habitat for critters other than summer vacationers. On an undeveloped island, different plants and animals that can tolerate different amounts of salt water and exposure to the air make their homes in different zones. Clams live beneath the sandy shore, while birds that prey on them scurry above. Grasses hold the dunes in place, and at the highest points of the island you can find trees and shrubs where songbirds and mammals live. Brackish marshes on the other side of the dunes host crabs and serve as a nursery where fish can eat and grow before venturing into the open sea. Wading shorebirds take advantage of this bounty. Beyond the marsh is the back bay and the mainland.

Ghost crab (NPS)

Sandpiper feeding frenzy

The US has more barrier islands than any other country in the world. Best known are New York's Fire Island, Texas's South Padre Island, the Outer Banks of North Carolina, and the Jersey Shore. If you spend a summer weekend at the beach, be sure to check out the wild side of things.
This week's information comes from Science News for Students.

Species of the Month

As the snow disappears from higher elevations in the west, mountain hikes are once again becoming possible. That's where you'll meet our Species of the Month, although you are more likely to hear it than to see it. The American pika, though it looks rather mousy, is actually related to rabbits. Living high up in the rocky slopes of the Cascades, Sierras, and Rockies, it lets out a high pitched squeal as an alarm call when it spots a potential predator or passing hiker.

Pika adding to its cache of food (NPS)

Scientific name: Ochotona princeps

Kingdom: Animalia (animals)

Class: Mammalia (mammals)
Order: Lagomorpha (hares, pikas, rabbits) 

Range: Mountains of western North America from British Columbia south to New Mexico

Habitat: Talus fields within mountain meadows

Pika on the rocks (NPS)

Lifespan: Up to seven years, average is three years
Diet: Grasses and forbs
Predators: Weasels, coyotes, raptors, martens, foxes, bobcats
Conservation Status: No special protection, though seven subspecies are considered vulnerable
Other information: This little critter looks like a big, chunky mouse or a rabbit with short ears. They are active during the day, gathering plants during the summer for immediate consumption and also to stockpile for the long winter ahead. Pikas build haypiles of grasses and forbs, selecting plants with the highest protein content they can find. Haypiles are kept outside during the summer to dry, then moved to the den for winter. Pikas do not hibernate; they remain awake in a tiny cave within the rocks and under the snow, eating their way through that haypile. Like other lagomorphs, they frquently consume their scats. Food is not totally digested, so they eat the scat to absorb more nutrients. Eating it a second time more fully breaks down the plant material. Pikas communicate though alarm calls and scent marking. Scent glands are on the cheek. They rub their cheeks on rocks to mark their territory.

Pika (NPS)

Look for pikas at Mowich Lake in Mount Rainier National Park. This week's information once again comes from the good people at UM's Animal Diversity Web.

Species of the Month

Halloween is right around the corner, so it’s time for another creepy crawly species of the month. We’ve covered bats and owls, so this year we’ll go to the spiders. Stop reading here if they creep you and come back next week. Grass spiders are a genus of several funnel weaving spiders, including the Pennsylvania grass spider. You’ll likely start noticing these robust spiders in your house as they venture inside to avoid the falling outdoor temperatures. We associate spiders with Halloween because they are at their biggest after growing all year.

Pennsylvania grass spider at my sister's house

Scientific name: Agelenopsis species

Kingdom: Animalia (animals)

Class: Arachnida (arachnids)

Order: Araneae (spiders)

Range: All of North America except Arctic areas

Habitat: Lawns, your house during fall

Grass spider in its natural habitat (Penn State)

Lifespan: One year

Diet: Insects

Predators: Birds

Conservation Status: No special protection

Grass spider in its web (Missouri Department of Conservation)

Other Information: Grass spiders build funnel or tunnel shaped webs in the grass, hence the name. Females lay eggs in sacs during late summer or early fall, with eggs hatching in spring. The eggs survive over the winter but adult spiders do not. Grass spiders are fast and typically avoid humans, but will occasionally bite with trapped and threatened. Information this week comes from Insect Identification, despite spiders not being an insect.