Animal Attraction

People are more like animals than we like to admit sometimes. Rather, we tend to believe that animals can be so human sometimes. One area where the lines between humans and animals can become blurred is that of courtship rituals and relationships. This Valentine’s Day let’s look at “love” in the animal world. Hopefully our finned, feathered, and furred friends don’t feel as awkward as we do.

Many times, in the animal world it is the female who chooses a mate. Males might compete with each other not by fighting, but other means. Bowerbirds build little houses with decorated yards to impress females. Prairie chickens and sage grouse gather in a lek, where the males display for the females. South American birds called manakins show like an 80s break dance fight from a movie. It reminds me of teenage boys trying to upstage each other to get a girl’s attention.

In other species, brute strength carries the day for males eager to win mating rights. Large mammals like elk and bison have a dominant male who controls a harem of females, unless a younger and stronger challenger is able to put him out to pasture. This behavior reminds me of countless schoolyard and lunchroom fights over a girl.

Once these critters become an item, how long does their relationship last? It depends on the critter, just like with us. Some species are monogamous pairs, some are promiscuous males, and some are promiscuous females. For those that have a hard time getting around, like corals and clams, it’s free love. Look around at our own society and you’ll see the same scenarios, though not always for the same reasons.

In promiscuous relationships it is the female who raises the young with no paternal help in most cases. The bison and elk, where a male controls a harem, are male promiscuous. He will mate with as many of the females as he can. His goal is to have as many offspring as possible, while the female’s goal is ensure that her offspring have the best chance of survival. Surely the strongest and most fit of the males has the genes that offer better odds.

Sometimes it is the female who gets around. Several species of primates and birds practice this. The female hopes for better reproductive success by keeping her options open. It may also have the advantage that comes with several males all believing the offspring are theirs. Since the male’s goal is to have as many offspring as possible, the uncertainty will make sure they are looking out for any that are potentially theirs.

Everyone’s favorite relationship is monogamy. A pair mates for life and we think it’s so sweet. It’s almost like they’re married. This behavior is seen in bald eagles and gray wolves, for example. In this situation, both parents care for the young. In most cases, the pair nest together year-round. Not so for the Laysan albatross like Wisdom, who we met a few weeks ago. While she has a monogamous partner, they spend most of the year apart, coming together only for the breeding season. Once they chicks fledge the nest, they all go their separate ways. Wisdom and her mate will see each other again next year.

The messiest mating strategy is dispersal. Wind pollenating plants (think of pine trees) use this method, as do many sea creatures. Some environmental cue triggers corals, clams, and other sessile critters to release sperm and egg cells simultaneously. The sea becomes a soupy mess as the currents mix everything together. The pinnacle of group sex, critters who have never met or even seen each other become proud parents of children drifting off to parts unknown.

Every species is adapted to whatever mating and parenting style works best to ensure the next generation will survive. A general rule of thumb: fewer offspring get more intense parenting, while more offspring get little to no parental care. Either way, parents are playing the percentages to make sure they win the mating game.

 This week's information comes from Nature Education and the Washington Post.

The Sage of the West

Let’s head back into the heat again this week and explore another warm, dry ecosystem. Sage scrubland is semi-arid and unless you live there, you probably aren’t familiar with it. Like the desert, it can appear to be devoid of life unless you know where to look.

Sage scrubland in Idaho (USFS)

The ecosystem is defined by sagebrush being the dominant plant species with hot, dry summers and cold winters. Most precipitation is winter snow and spring rain. Sage scrubland ecosystems are found in the Intermountain West and California’s coastal chaparral ecosystem.

Many animals call the sage scrubland home. Small mammals and reptiles are well represented in the list of fauna. The endangered black-footed ferret is among them, and it was in Wyoming’s sage scrubland that a colony was discovered after the species had been given up as extinct. They were all captured and put into a captive breeding program which has seeded recovery efforts throughout the West. Larger mammals include elk, mule deer, and pronghorn.

Black-footed ferret (USFWS)

Birds of prey are common inhabitants of this ecosystem. The sage grouse (of course) also calls this area home. This threatened bird relies heavily on the sagebrush for its survival. Not only is sage a staple if its diet, it also uses the plant for cover.

Male sage grouse (USFWS)

Sagebrush, the dominant plant in this ecosystem, provides sustenance for species other than the sage grouse. When the deer and the antelope aren’t playing, they can be found nibbling on sage brush. It is especially important during the winter when other lower plants are buried under snow. 

Like so many other habitats in the world, sage scrubland is in danger. Development destroys or fragments the habitat. Oil and gas drilling scare away resident critters and disrupt migrations. Invasive plants crowd out the natives and create a vegetation density conducive to fire. While sagebrush can withstand low intensity fire, hotter fires fueled by invasive cheatgrass destroys it. Agriculture converts sage land to crop land.

Sagebrush in Oregon

There is hope, of course. Most sage scrubland is in sparsely populated areas so it is disappearing at a slower pace than other areas. Agriculture, which can be destructive to this ecosystem, can also be a conservation partner. It makes a great low-maintenance rangeland if done sustainably.

Sage scrubland is an important, but unheard of ecosystem. Most people think of the Intermountain West as just drive-through or fly-over country. Eastern Washington is a million shades of brown from 30,000 feet. But while driving across eastern Oregon, southern Idaho, and northern Wyoming I was quite taken with the beauty and solitude of the seemingly endless sea of sage.

This week's information comes from US Fish and Wildlife Service, Oregon Department of Fish and Wildlife, and Wyoming Game and Fish Department.

Road Trip Adventure- Volcanic Idaho

Continuing on our road trip, this week’s Nature Minute takes us to Idaho’s Craters of the Moon National Monument and Preserve. Located in south central Idaho, the area was once a hotbed of volcanic activity. Ancient lava flows created a unique landscape and habitat. Enjoy this week’s story from the road.

The lava flows that give Craters of the Moon its signature look and name sprang from the Great Rift between 15,000 and 2,000 years ago. The lava beds cover over 1000 square miles, flowing from 25 vents that spewed in at least 8 volcanic events during that time period. Craters of the Moon is the largest of several lava beds in the Great Rift.

Volcanic landscape of Craters of the Moon

Lava in the midground, sagebrush steppe in the
foreground and background

Geological features of the Monument are spatter cones, cinder cones, fissures, lava tubes, and kipukas. The cones and fissures are volcano types. Lava tubes and kipukas are formed by lava movement.

Spatter cones are formed when thick lava is ejected from a volcano. It remains molten when it hits the ground, but due to high viscosity, the blobs of lava do not flow away. Rather, new molten blobs are ejected and they stick together, forming a cone. Cinder cones form similarly, but the lava blobs cool and harden in mid-air, becoming lava bombs (actual geological term). The size and shape of the bombs is dependent on gas content.

Spatter cone (NPS photo)

Fissures are large volcanic cracks in the ground. A full-length fissure eruption is probably the rarest of all volcanic eruptions. Spatter and cinder cones can form in a fissure if it becomes clogged in any area. 

Lava tubes form when the outside of a lava flow cools, forming a hard rock shell. After the remaining molten lava drains, the hollow tube remains. I have been inside a lava tube, the Ape Cave at Mount Saint Helens in Washington.

Lava tube (Oregon State University photo)

Kipukas are islands of older lava flows surrounded by newer lava flows. Vegetation on kipukas is different from the surrounding lava flow areas. At Craters of the Moon, the kipukas are islands of sage steppe surrounded by black lava rock.

Kipuka (NPS photo)

Despite its barren appearance, Craters of the Moon supports a diverse ecological community. Plants include sagebrush, prickly pear, limber pine, and Indian paintbrush. Animals in the Monument include the pika, sage grouse, pygmy rabbits, northern harrier, and common nighthawk.

Limber pine

While visiting, I observed a northern harrier overhead. I took a nice stroll through the Devil’s Orchard, so named by a 19^th century preacher who failed to see beauty in Creation and declared the place to be a garden fit for the devil. I enjoyed seeing the lichen that are working around the clock to turn rock into soil so larger plants can colonize. The twisted branches of the limber pine, knotted by mistletoe, set against a stark black backdrop made for an eerie sight. I enjoyed my brief visit and would like to return for a more in-depth look around. I chose not to linger because Craters of the Moon was the undercard for the main even, Yellowstone.

Limber pine with "witch's brooms"

Polished lava rock with swirls

Hardened slow-moving lava flow

Information this week comes from the National Park Service about kipukas, including the picture above. Great Rift information comes from a paper by the folks at Idaho State University. Photo credits go to National Park Service (spatter cone) and Oregon State University (lava tube). All others are my own.