Seasonal Changes:

A look at reindeer biology through out the year.


January

January in the north means more winter, but reindeer continue to thrive. The bulls have been losing weight since the onset of rut, but this weight loss will finally begin to slow. Mature bulls who did not shed their antlers in December will drop them soon, leaving only younger animals and pregnant females with antlers.

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February

It's February and it's beginning to lighten up as the sun slowly returns. With the longer days comes more antler shedding. By this time, all but the youngest bulls have dropped their antlers, though the pregnant females are still holding on to theirs. The bulls are still very thin, but they begin to eat more at this time of year and will start gaining weight soon. Some of them will even begin to grow a new set of antlers!

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March

Though it's still winter, March brings long sunny days and milder temperatures. By this time, all of the males, including steers and yearling bulls, have lost their antlers and are beginning to grow new ones. This is also the time of year when the bulls begin to gain weight.

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April

April brings reindeer babies! The days are getting warmer now, just in time for calving season. Within several days of giving birth, the females will drop their antlers. Shortly thereafter, they will begin to grow a new set. The females begin to eat a little more but don't gain a lot of weight, due to the high metabolic cost of lactation. Bulls however, continue to gain weight, a trend that will continue throughout the summer.

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May

May brings more reindeer calves and subsequent shedding of antlers by females. Nearly all of the reindeer have the beginnings of new velvet antlers by now. Even the young calves will start to grow a set of antlers before long! Spring also brings the emergence of a few green plants. This is an important time in the nutritional cycle of reindeer. Their lichen-based winter diet has been very high in carbohydrates, but lacking in protein and minerals, key nutrients for growth. With all the antler growth taking place, not to mention pregnancy and lactation, the reindeer are quick to seek out nutrient-rich forages.

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June

June brings the longest days of the year, and the young plants are growing quickly with all the sunlight. However, even with an increasing selection of nutritious green forage, lactating females remain thin. It takes a lot of energy to produce enough milk to support a calf and there's not usually left over to fatten up the mother. The bulls, on the other hand, are gaining weight well. The steers, who tend to maintain their weight throughout the winter, are usually in good condition this time of year.

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July

July means more sun and more vegetation. The animals continue to eat and gain weight. Their antlers are almost fully grown and are beginning to calcify. Late in the month, the calves will be weaned, finally giving the females a chance to put on a little weight before winter.

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August

August is the breeding season (called rut) for reindeer. The females come into estrous, and the bulls begin to exhibit signs of rut, including swollen necks and increased glandular secretions. The bulls are at their heaviest weight of the year, but eat very little once they enter rut. The result is a steady weight decline that will continue into the new year. This is also the time of year when the bulls shed their antler velvet.

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September

Rut continues through September, with both the males and the females eating less. The bulls will continue this trend until rut is over. However, the females will begin to eat more once they are bred. Females begin to shed their antler velvet in September, exposing the hardened bone antler beneath.

Click here to learn more about how these natural changes inform our management techniques on the farm.


October

By October, the days are becoming noticeable shorter and the temperatures are dropping. Rut will be over by the end of the month. The bulls continue to lose weight, but the females will be at the heaviest weight of the year. Their feed intake decreases at this time of year, as the snow falls and foraging becomes harder. Despite the growing fetus inside of them, they don't gain weight during the winter due to the metabolic cost of pregnancy and the reduced forage availability. The steers, who are also at their heaviest weight of the year, will maintain their body condition throughout the winter.

Click here to learn more about how these natural changes inform our management techniques on the farm.


November

November takes us deeper into winter, but the reindeer continue to do well. The bulls still have low body weights due to the rut and pregnant females may experience a slight weight loss between now and the time they give birth but overall, reindeer are remarkably adapted to the harsh climate at high latitudes. (Click here for a fun and interesting slide show featuring these adaptations.)

Click here to learn more about how these natural changes inform our management techniques on the farm.


December

December brings even more darkness and cold, and finally, the bulls will stop exhibiting the behaviors of rut. However, they continue to lose weight -as much as 25% of their total body weight by now. The older bulls will also begin to lose their antlers. The younger bulls tend to hold on to their antlers a little bit longer, and the females will not typically drop theirs until after they have given birth in the spring. This gives pregnant females the upper hand when guarding their food craters from other reindeer.

Click here to learn more about how these natural changes inform our management techniques on the farm.


Contact Information
Reindeer Research Program
Page Last Modified: 05/15/15 1:43 pm by: dsblodgett@alaska.edu