Primarily grazers but can be very selective, preferring the tender parts of grasses, sedges, herbs and woody species. They will often be seen feeding in and close to cover but often venture out into the open especially on agricultural/horticultural crops where they eat the weeds as well as the crops themselves. Average browse height is 75cm-90cm.
Rut in November/December. In reasonable conditions adult does will produce twins although pregnancies with 4-5 foetuses are not uncommon. Does have a breeding life of 6 years or more with fawns becoming sexually mature at 5-8 months of age. Confirmation of pregnancy is possible from January using the presence of embryos. Survival rate of fawns is often poor, especially in cold, wet weather. Fawns are born in May/June and most does cease lactation by September.
Male and female can be hard to distinguish at any age, the presence of long, visible upper canines can help to distinguish males. In young males, canines erupt in autumn and by end of winter are about half their final length so are often just visible then. CWD have no antlers.
Difficult to age. Fawns rapidly approach adult weight by the time they are 1 year old. Older CWD tend to be stockier and broader across the back.
The upper canines of males reach full length by 18 months to 2 years. The length of the canines is not a good indicator of age. Most wild CWD are younger than 8 years.
Coat change is normally April/May and Sept/Oct. Very late coat change may be an indicator of poor health. CWD fawns have a high mortality rate in cold, wet weather.
CWD have a relatively small distribution and reports of damage caused by them are limited. CWD do not seem to eat ground level flowering plants to quite the extent that muntjac might. Agricultural and horticultural crops can suffer localised damage. Damage on cereal crops often stops as soon as the crops are sprayed. Bark scraping with the tusks may occur, especially around the rut.