Penn State Extension


Deer Keds

Lipoptena cervi (Diptera: Hippoboscidae)


The deer ked is an introduced species of biting fly originally found in Europe, Siberia, and Northern China. It is recorded in nature as a parasite on red deer, roe, elk, and sika deer in the Old World and on whitetail deer, elk, horses, cattle and humans in North America. Under laboratory conditions it will also feed on dogs, house mice, moles, monkeys, pigeons and domestic fowl. On humans, the deer ked will engorge on blood in 15 to 25 minutes. The bite is barely noticeable and leaves little trace at first. Within three days the site develops into a hard, reddened welt. The accompanying itch is intense and may last 14 to 20 days. This reaction is probably the result of the body’s reaction to the fly saliva. Currently, deer-keds are not known to vector diseases to humans or domestic animals.

Life History


Winged adult deer keds are flying about in early autumn (and sometimes through December) in search of deer. As soon as the fly alights on a host it begins to burrow through the fur, shedding its wings by breaking them off close to their bases. The keds then take a blood meal, mate and after an indeterminate period the female will birth a mature larva which will begin to pupate. After birthing, the female will again feed, mate and produce another larva. It is unclear how many larvae are produced per female.


Adult deer keds are 3.5 - 5 mm (1/8 - 3/16 inches) in length. The head, thorax and abdomen are flattened and leathery in appearance. The head and thorax are brown and the abdomen is a greenish yellow with light-brown plates on the posterior segments. Deer ked legs are stout with large dark claws. Overall, the ked is covered with strong, dark hairs.


Deer keds are frequently mistaken by hunters as ticks. Keds may superficially resemble ticks but the former are typically larger, highly mobile and are found on the deer belly. Ticks are attached to the skin, do not move around much and are usually found about the head and neck.

It is not necessary to control deer keds. They will not reproduce on any host other than deer and because most venison is hung in coolers or outside during cold weather the keds will not be able to move about. Hides can be placed in plastic trash bags, frozen, and the keds can then be shaken off.


Pesticides are poisonous. Read and follow directions and safety precautions on labels. Handle carefully and store in original labeled containers out of the reach of children, pets, and livestock. Dispose of empty containers right away, in a safe manner and place. Do not contaminate forage, streams, or ponds.

Authored by: Steve Jacobs, Sr. Extension Associate

April 2009

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