Bat Biology

Home » Bat Biology
Bat Biology 2017-09-22T12:03:39+00:00

bat biology

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

  • 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

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 batBrazilian “Mexican” Free-tailed Bat

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.