Roe deer
- European roe milk contains 9.6% fat and 9.2% protein, which is higher than 3.7% and 3.3% in cow's milk.
- The European roe deer lives at altitudes up to 3500 m above sea level on the Caucasus, although it usually prefers areas between 300 and 600 m above sea level.
- European roe (Capreolus capreolus) are the only ungulates with a latent period of pregnancy. A fertilized egg at the morula stage enters the uterus and quickly reaches the blastocyst stage, but then the embryo develops almost not at all for 4.5–4 months.
- At the beginning of the season, male European roe deer actively defend their territory, and at the end of the rut, they make sorties to search for females in estrus.
- Sexual maturity in young male roe deer occurs at the beginning of their second year, but they only begin to reproduce in their third to fourth year of life, being physically outmatched by adults.
- The European roe deer usually lacks upper incisors (rarely in young males) and has permanent upper canines.
- The olfactory surface area of the European roe's nostrils exceeds 90 cm², and the number of olfactory cells is 300 million, which is 30–40 times greater than in humans.
- In the European roe deer, the sense of smell plays a major role in social behavior — of 42 elements of social behavior, 26 are related to olfactory perception.
- European roe deer do not undertake winter migrations, unlike Siberian roe deer, although many females return in the autumn to the places from which they came in the spring to their calving areas.
- The European roe deer is one of the smallest deer in Europe.
Age
European roes typically live from 7 to 15 years, with a maximum lifespan of 17 years and 6 months, and a theoretical lifespan ranging from 8 years and 9 months to 17 years and 6 months; the age of sexual maturity ranges from 1 year and 2 months to 2 years, and the young are born with their eyes open and begin walking immediately. The embryo stage involves the development within the mother, during which development pauses temporarily after fertilization; the fawn stage is a newborn roe deer that hides in grass for the first few weeks and feeds on its mother’s milk, lasting from 1 day to 3 months. Following this, the young after rapid growth stage sees the animal independently foraging and growing, lasting from 3 months to 2 years. The adult stage begins at 2 years and lasts up to 12 years, during which males defend territory and possess antlers, while females give birth to fawns.
Phenotype
The European roe deer’s young have fur with white spots for camouflage in grass; after a period of rapid growth, the species’ young have reddish fur in summer and more gray fur in winter. Adult European roes have short, reddish fur in summer and long, gray fur in winter, and a large white spot on their rump is visible from a distance. The adult has small antlers with three branches that fall off each year and regrow. The species' thin and strong legs allow for fast running and jumping over bushes.
Physiology
European roe deer have a body length ranging from 60 centimeters to 0.9 meters and weigh from 23.9 to 24.02 kilograms; the embryo stage has a body mass of 0 grams, while the fawn stage exhibits a body mass between 1 and 2.5 kilograms and a body length from 40 to 70 centimeters. The young after rapid growth stage displays a body mass from 5 to 18 kilograms and a body length from 50 to 75 centimeters; the adult stage has a body mass from 20 to 28 kilograms and a body length from 60 to 85 centimeters.
Habitat
The European roe deer inhabits land, terrestrial forest, and mountain tundra, preferring temperate mixed forests with a summer from cool to warm, where the summer is not hot, from +15 to +25 °C, as well as flooded meadows with an abundance of grass. The species is found in taiga with a cold winter and an abundance of coniferous trees such as spruce and pine, and can rise to an altitude above sea level up to 2 km. The climate for the European roe deer is characterized by constant humidity and a large amount of rain, and summer can be warm and pleasant, with a winter that is not very cold.
Shelter
European roe deer inhabit dense thickets or tall grass and do not have a permanent or long-term shelter. The species does not utilize a fixed refuge, and the female uses berries and grass as materials for shelter. These shelters serve purposes such as protection from predators and rest.
Geography
The European roe deer occupies the Palearctic biogeographical region and inhabits several ecosystems, including Celtic broadleaf forests, broadleaf forests of Western Europe, Baltic mixed forests, European Atlantic mixed forests, Sarmatian mixed forests, and Carpathian mountain forests.
Feeding
The European roe deer is an herbivore, consuming only plants; during summer, the species feeds on fresh leaves, grass, and shoots, while in winter it eats branches, buds, and dry grasses. It obtains food by grazing, and its diet includes grass, leaves, shoots, buds, berries, mushrooms, acorns, thorny and prickly plants, young shoots and sprouts, and nuts. The species employs a grazing feeding strategy, with a daily food requirement ranging from 0.8 kilograms to 2.5 kilograms. Young roe deer, known as fawns, are nourished with milk. Predators such as bears, eagles, and wolves hunt the European roe deer.
Reproduction
European roe deer inhabit and develop on land, outside of bodies of water, and their offspring develop in nests built on the ground or close to it, with nests located directly on the surface of the ground. The species reproduces through live birth, with young being born alive on land, not hatching from eggs or larvae; mating occurs in summer, and embryonic development is delayed by several months. Gestation lasts 5 months, and fawns are typically born in spring, with a litter size of 1 to 3. The female has 1 to 3 offspring and exhibits parental care within the nest on the ground, where only the mother shows care for the young. Sexual reproduction is always accomplished through fertilization, without generation changes; males reach maturity from 1 to 2 years of age, and the reproductive interval is 1 year.