Parasites and Diseases
Moose Fly

A Field Guide


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Bloody wounds on hind leg of moose due to fly bites

What causes small open wounds on the hind legs of moose?
  • These wounds are caused by a biting fly commonly known as the “moose fly.” Its scientific name is Haematobosca alcis. Moose flies are slightly smaller than a common housefly.

Where are the flies found?
  • The flies are found wherever moose are found in Alaska.
  • Apparently, the flies do not attack other members of the deer family (such as deer, elk, or caribou).

What are the signs of moose fly attacks?
  • The flies bite the hindquarters of moose just above the hock. Hundreds of flies may attack a moose at one time. The numerous bites produce wet open sores, measuring up to 1 inch in diameter. The wounds are often bloody.

How can I protect myself?
  • The flies do not attack humans.

Can I eat the meat?
  • Neither the flies nor the wounds affect the edibility of the meat in any way. The meat is safe to eat.

Samples to collect
  • Report observations or submit photos.
  • To report an occurrence or to submit a sample for identification/analysis, contact the DWC Wildlife Disease Surveillance reporting hotline 907-328-8354, send an email to or visit your local ADF&G office.