deer fly vs horse fly

2 min read 18-03-2025

Meta Description: Learn to distinguish between deer flies and horse flies! This comprehensive guide explores their differences in appearance, biting habits, and the best ways to protect yourself from these pesky insects. Discover how to identify these biting flies and what to do if you're bitten. We cover everything from size and color to their annoying bites and effective repellent options.

Summertime often brings unwelcome guests in the form of biting flies. Two common culprits are deer flies and horse flies. While both can deliver a painful bite, there are key differences between these two insects. Understanding these distinctions can help you better identify and protect yourself from their attacks.

Identifying Deer Flies and Horse Flies: A Head-to-Head Comparison

Both deer flies and horse flies belong to the family Tabanidae, but their appearances and behaviors differ significantly.

Appearance

Horse Flies:

Size: Larger, typically 1/2 to 1 inch long.
Color: Often dark-colored, sometimes with a greenish or bluish tint. They can have patterned bodies.
Eyes: Large, widely spaced eyes, often with iridescent coloring. Males often have eyes that touch.
Wings: Usually clear or slightly smoky.

Deer Flies:

Size: Smaller, generally 1/4 to 1/2 inch long.
Color: More mottled or patterned appearance, often with stripes or spots on their bodies. They frequently have a more brightly colored abdomen (often yellow and black).
Eyes: Eyes are more closely set. They are usually larger in the males.
Wings: Clear, often with dark markings.

Biting Habits

This is where the real difference lies. Both are hematophagous (blood-feeding) but their approaches vary:

Horse Flies: These are aggressive biters. Their mouthparts are designed to slice through skin, causing a sharp, immediate pain. They’re more likely to bite during the day. Their large size makes them easy to spot before they strike.

Deer Flies: Deer flies are also aggressive but sneakier. Their bite is less immediately painful than a horse fly bite, but it is still quite irritating. The bite often feels like a pinprick. The bite then may swell and itch intensely afterward. They are less likely to bite around dusk.

Habitats

Both deer flies and horse flies prefer moist environments, often found near bodies of water, marshes, or wooded areas. However, horse flies tend to prefer more open areas, while deer flies may be found in more heavily wooded or shaded locations.

How to Protect Yourself from Deer Flies and Horse Flies

Protecting yourself from these biting pests is crucial. Here are some effective strategies:

Repellents: Use EPA-registered insect repellents containing DEET, picaridin, IR3535, or oil of lemon eucalyptus.
Clothing: Wear light-colored clothing that covers as much skin as possible.
Timing: Limit outdoor activities during peak biting times, usually dawn and dusk for deer flies and midday for horse flies.
Fans: Fans can help deter flies, as they have difficulty flying in wind.
Screens: Use screens on windows and doors to prevent flies from entering your home.

What to Do if You're Bitten

Both horse fly and deer fly bites can be quite irritating. Here's what you can do:

Clean the bite: Wash the area thoroughly with soap and water.
Ice pack: Apply a cold compress to reduce swelling and pain.
Anti-itch cream: Use an over-the-counter anti-itch cream or hydrocortisone cream to relieve itching.
Monitor for infection: Watch for signs of infection, such as increased redness, swelling, or pus. Seek medical attention if necessary.

Understanding the differences between deer flies and horse flies is the first step in protecting yourself from their bites. Remember to use repellents, wear protective clothing, and take appropriate measures if you are bitten. Stay safe and enjoy the outdoors!