Moose are the largest and heaviest living members of the deer family Cervidae. The largest North American moose are in the Alaska and Yukon Territory, moderate size moose span from Alberta, Canada to the east coast, and the smallest moose are located in a narrow band of the Rocky Mountains in Montana, Wyoming, and Colorado. Bull moose range in size from 900 to 1600 pounds and reach a height of over six feet at the shoulders. Adult cow moose are about 15 percent smaller, but still impressive. Moose are cold-weather vegetarians found in the northern boreal and mixed deciduous forests.

Like other members of the deer family, bull moose grow and shed antlers annually. Antlers are large and palmate, not dendritic like other deer species. Moose antlers begin growing in April as bones covered with skin and blood vessels, known as velvet, and reach maturity in September. The blood-enriched velvet is shed at that point, before rut, the mating period. Moose antlers are the fastest growing bone of any living species, weighing over 40 pounds at maturity.  Antlers are shed in winter, typically in December and January.

Rut occurs in late fall, usually late September to early October. Bull moose closely follow mature cow moose waiting for them to enter estrus. Pheromones are detected by bulls with the Jacobson organ, a tiny sensing device in the upper palate of moose. A bull will tilt its head back and inhale through its teeth, detecting pheromones as air passes over this tiny organ in the palate; this is known as the Flehmen Response. Mating occurs when the female is receptive.

Cow moose birth their young in early May, timed with the emergence of green leaves after a long, cold winter. Twins are not uncommon, and the birth weight of the calf is approximately 30 pounds. Cow moose will closely protect and feed their calves for the first few months, and the calves will begin to wean and transition to leafy forage in late summer. By late fall, calves’ weight will have multiplied, reaching up to 300 to 400 pounds. Calves will remain with their mothers until the following spring, when the cow moose will      chase them off before she gives birth to new offspring.

Many large herbivores, such as bison and cattle, are grazers, which consume a diet rich in grass and forbs (small plants) at ground level. Moose, however, are “browsers,” consuming leafy plants elevated from the ground. If available, the willow plant is typically preferred, but their diet consists of over 80 different plants, both terrestrial and aquatic. Aquatic plants contain increased amounts of sodium, a mineral necessary for the metabolic processes of animals.  Adult moose consume 30 to 50 pounds of forage daily.

In winter, after deciduous trees have lost their leaves, moose consume twigs, bark, and conifers. Conifers, because they are green and “alive,”, contain many      more nutrients than twigs and bark. However, conifers are more difficult to consume because they have plant secondary metabolites (PSM). PSMs, such as tannins and phenols, can cause dietary issues. Moose are able to consume a measured number of tannins because of their four-chambered stomachs. The first chamber, the rumen, has microbiota that can assist with the digestion of these PSMs. Moose consume approximately 35-40 percent conifers, such as balsam fir and cedar, and 60 percent deciduous twigs. A moose will lose 15 to 20 percent of their body mass during the winter because of this limited diet.

Moose are listed as an animal of least concern with stable populations across most of the upper northern hemisphere. However, they are cold-weather animals and suffer the effects of increased temperatures. As the ambient temperature rises above 50 degrees, moose will bed down and reduce activities. Moose are also susceptible to parasites carried by deer. As temperatures have warmed, the range of deer has expanded. Brainworm, caused by Parelaphostronglus tenuis, is transmitted by deer to moose, and causes a fatal neurological disease in moose.

From Russia to most northern circumpolar regions, the majestic moose has filled the hearts of many with its impressive size, large antlers, and somewhat awkward appearance. Moose lovers are found searching for moose near ponds and in the forest, as well as in deep snow in the winter.

From Russia, With Love

Written and Photographed by Moose Henderson

Environmental Spotlight

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