Can a female deer have antlers

Baden-Wuerttemberg

A rarity - "horned doe" with raffia-covered poles

A report from our everyday laboratory work

Dr. Anna Katharina Schwalm

 

Doe or roebuck? The most striking feature of the sexual dimorphism in roe deer is the antlers of the roebuck ("horns"), which identifies it as a male animal from a distance. But is this always true? The discovery of a deer with antlers and female genitals raises questions.

 

You are amazed - the discovery of an accidental game on the side of the road in April 2020 surprised: A roe deer with female genitals and protrusions on the forehead seems paradoxical and prompted those authorized to hunt the animal to bring the carcass to us for dissection.

 

Dissection findings

The external inspection revealed clear primary and secondary sexual characteristics, such as the vagina and a formed udder.

In addition, the animal had paired, deformed and bony forehead growths. These were cauliflower-like at the base of the skull and each provided with unevenly long bast-covered rods. The bast was partly swept away.

 

Fig. 1 and 2: Deformed forehead growths with raffia-covered poles in a female roe deer (doe). The reddish periosteum is partially visible.

 

In addition to pathological changes as a result of blunt trauma, the animal was severely infested with ectoparasites (ticks, deer lice flies). An intact twin pregnancy was also demonstrated during the dissection.

 

"Horned doe"

"Horned" doe are rare, but are known [3]. Forehead growths can be formed in females. The range of variation of the forehead outgrowths is very large and ranges from bony elevations on the forehead to rod-like structures [1]. Bast-covered poles are even more rare [1, 4].

A Norwegian study recorded the occurrence of rose bushes (front cones) in female deer during the hunting season over a period of 14 years. 50 rickkeys, 49 young rickkeys (1.5 to 2.5 years old) and 27 older rickkeys (at least 3.5 years old) were included. In the young animals (fawns and 1.5 year olds) the incidence of rose bushes was around 6% each. In the older doe it was almost 15%. Only one doe wore real antlers (1.7%) [2].

 

Possible causes

There is hardly any scientific work on the causes. Forehead growth is induced in male cervids (deer family) by the sex hormone testosterone. In the female animal, this activation is inhibited by a high concentration of estrogen.

A disruption or age-related change in the hormonal balance, as well as testosterone-forming tumors, can lead to the formation of forehead growth in doe [1]. For example, it has been described that in doe with advanced age and decreasing estrogen levels, forehead protrusions can increase in size [1, 4]. Furthermore, one-sided ovarian hypoplasia (underdevelopment of the ovary) should be addressed, so that although the hormonal balance is influenced, an intact pregnancy is still possible [4].

In addition to hormonal influences, unspecific irritation of the periosteum that forms antlers, which is common in both male and female animals, is a possible cause of antler formation [1].

 

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[1] Kierdorf U and Kierdorf H. A rick wig of exceptional strength. Z. Jagdwiss. , 31: 242-246, 1985 (1985).

[2] Mysterud A and Østbye E. The frequency of antlered female and anterless male roe deer (Capreolus capreolus) in a population in south-east Norway. Z. Jagdwiss. 45: 208-211, 1999 (1999).

[3] personal communication with FVA (Forestry Experimental and Research Institute Baden-Württemberg)

[4] Stubbe C. Roe deer. 5th edition, 118-119, 2008.

 

 

Article first published on September 1st, 2020