Agile and fast in case of danger, fallow deer can run at a maximum speed of 50 km/h (30 mph)[7] over short distances.

[8] A 1977 study of European fallow deer in the New Forest of Britain found that European fallow deer were selective mixed feeders, feeding primarily on grass (and to a less extend on herbs and browse) during the spring and summer (March–September), while primarily feeding on acorns and other mast during autumn (from September) until late December, with winter foods including grass as well as shrubs like brambles, bilberry, heather, holly, as well as ivy and coniferous material.

[9] During the Last Interglacial (also known as the Eemian) around 130-115,000 years ago and prior, European fallow deer were widely distributed over Europe, occurring as far north as the British Isles.

During the Last Glacial Period (115,000-11,700 years ago) the range of the species collapsed due to unfavourable climate conditions, surviving in refugia in Anatolia and probably the Balkans and possibly elsewhere, though the fossil record of their distribution during this time is sparse.

[14] Contrary to that, remains indicate that reduced numbers survived in several parts of the country like in Thessaly, Peloponnese and Central Greece, increasing and becoming common during mid Neolithic, but mostly east of Pindus mountain range and especially in Macedonia and Thrace.

[15][18][19][20][21][22][23][24][25] In Bulgaria, the autochthonous population of fallow deer is believed to have declined and disappeared after the 9th or 10th centuries, and the species was reintroduced there much more recently.

[27] A male fallow deer was captured in Thrace in 1977 and translocated to Düzlerçamı, suggesting that a small population existed there at that time.

[29] A 2024 genetic study suggests that the Balkans served as one of two refugia for fallow deer during the glacial periods, alongside Anatolia.

[10] The Rhodian population of European fallow deer is smaller on average than those of central and northern Europe, though they are similarly coloured.

[10] Outside of Europe, this species has been introduced to Algeria, Antigua and Barbuda, Argentina, Australia, Canada, Cape Verde, Chile, the Comoros, Cyprus, the Falkland Islands, Fernando Pó, Israel, Lebanon, Madagascar, Mauritius, Mayotte, Morocco, New Zealand, Peru, Réunion, São Tomé, the Seychelles, South Africa, Tunisia, and the United States.

[36][37] The European fallow deer was introduced to Victoria Island in Neuquén Province by billionaire Aaron Anchorena, who intended to increase hunting opportunities.

[citation needed] The European fallow deer is listed as an invasive species in the province of British Columbia.

Recent finds at Fishbourne Roman Palace show that European fallow deer were introduced into southern England in the first century AD.

[41] European fallow deer are now widespread on the UK mainland and are present in most of England and Wales south of a line drawn from the Wash to the Mersey.

European fallow deer adapted extremely well to the South African environment with access to savanna grasslands, particularly in the cooler climate ranges such as the highveld.

Occasional reports of wild European fallow deer in Pennsylvania and Indiana are generally attributed to escapes from preserves or farms.

A herd of white European fallow deer is located near Argonne National Laboratories in northeastern Illinois.

[citation needed] A small herd, believed to be the oldest in the United States, exists in the Land Between the Lakes National Recreation Area (LBL) in far western Kentucky and Tennessee.

[citation needed] European fallow deer are highly dimorphic, polygynous breeders;[50][51] the breeding season or rut lasts about 135 days.

[53] Different populations, environmental variation, size, and even age can determine the type of variation within a European fallow deer mating system,[53] but lekking behaviour is the most commonly found and studied in nature; variation can be explained by three characteristics (1) the optimal strategy under specific environmental or social conditions, (2) the strategy of an individual may be dependent on the strategies of other individual males within the same population, and (3) individual males may be less capable at gaining access to females, since they can be outcompeted by other males that are more capable.

[52] Female European fallow deer are polyestrous; they are receptive to males during multiple periods of estrus throughout the mating season while not gestating.

[55] Most of the detailed research on the ecological characteristics and behaviour of European fallow deer occurs in large blocks of woodland, which means some bias may be present.

[50] European fallow deer seem to have a preference for older forests with dispersed areas of grass, trees, and a variety of other vegetation.

[50] Since European fallow deer are polygynous species that congregate once every year, males must fight to obtain access to estrous females.

[63] Male fallow deer are highly competitive during the rutting season; successful mating depends mainly on body size and dominance rank.

[65] Among ungulates, European fallow deer exhibit one of the most outstanding examples of sexual dimorphism, as males are much larger than females.

[64] Body size is important during male-male agonistic interactions and endurance rivalry, while females tend to have a preference for larger males.

[64] In a study done by McElligott et al. (2001), it was found that mating success was related to body size, pre-rut and rut rank.

Maternal investment early in life can be critical to the development of body size, since it can be quite variable at that stage depending on resources and habitat type.

Rhodian fallow deer also damage summer crops and due to a lack of a compensation system, persecution against the population could happen.