Little Brown Bat – credit: MerlinTuttle.org
BAT BIOLOGY
Little Brown Bat
- Average Length (Adult): 3 – 3 3/4” tall.
- Average Wingspread: 8 3/4” – 10 1/2” wide.
- Ear Height: 1/2 – 5/8”
- Average Adult Weight: 1/4 – 1/3 oz.
- Mating Season:Fall or in the Spring. Fertilization delayed till Spring.
- Gestation:4-7 Weeks
- Average # of Young Born:1
- Month Born: Late May – Early July
- Weaned: 6 – 9 Weeks
- Life Span:6 – 7 Years
- Fur Color: Yellowish brown to olive brown.
- Severely impacted by White Nose Syndrome in many areas.
Big Brown Bat
Big Brown Bat – credit: MerlinTuttle.org
- Average Length (Adult): 3 3/4” – 5” tall.
- Average Wingspread: 12 ½” – 13 3/4” wide.
- Ear Height: 5/8” – ¾”
- Average Adult Weight: 1/2 – 3/4 oz.
- Mating Season:Fall, Winter, or Spring
- Gestation:4-7 Weeks
- Average # Young Born:2
- Month Born:May – July
- Weaned: 4 – 5 Weeks
- Life Span:Up to 19 Years
- Fur Color: Long dark brown fur.
Evening Bat
Evening Bat – credit: MerlinTuttle.org
Nycticeius humeralis
- Average Length (Adult): 3 5/8” – 3 3/4” tall.
- Average Wingspread: 10 ¼” – 11” wide.
- Ear Height: ½”
- Average Adult Weight: 1/10 – 1/3 oz.
- Mating Season: Fall Fertilization delayed till Spring.
- Gestation: 4-7 Weeks
- Average # Young Born: 2
- Month Born: June – Early July
- Weaned: 6 – 9 Weeks
- Life Span: 2 Years
- Fur Color: Short sparse dull brown fur.
Brazilian “Mexican” Free-tailed Bat
Mexican Free-Tailed Bat – credit: MerlinTuttle.org
Tadarida brasiliensis
This species is the smallest of the free-tailed bats in the United States. It has a very distinguishing tail that extends beyond it’s rump.
- Average Length (Adult): 3 5/8” – 3 3/4” tall. Females are larger than males.
- Average Wingspread: 11” wide.
- Ear Height: 1/4” – 1/2”
- Average Adult Weight: 3/8 – 1/2 oz.
- Mating Season: February – March
- Gestation: 11 – 12 weeks
- Average # Young Born: 1 Per Year
- Month Born: June
- Weaned: 4 – 7 Weeks
- Life Span: 18 Years
- Fur Color: Dark brown or dark gray.