Now Playing Tracks

#SpookyScience: Scarier Than Bats is the Fungus Threatening Them

By: Emily Weidner, USFWS Biologist

image

Photo: Long-eared myotis (Myotis evotis) with forearm band. Credit: USFWS

Bats managed to find a niche not many other animals occupy, the night skies. There are big bats (Megachiroptera) and small bats (Microchiroptera). Chiroptera means “hand-wing.” Bats earned that moniker since membranes stretch between the fingers of their little bat hands forming their wings. Oregon has approximately 15 species of little bats.  Some migrate, some hang out in caves, some roost in itty-bitty rock crevices, and some like to roost wedged between slabs of bark in an old juniper tree. Bats echolocate their food with a series of clicks emitted from their larynx. The frequency and duration of their clicks depend on whether they’re foraging or have acquired a target (i.e., a tasty snack).  They can eat up to 1,000 insects every hour!  

image

Photo: Looking for wing damage; We then assign each bat a wing damage index number for each wing (0 = none to 3 = high). Credit: USFWS

Many folks worry about bats and diseases as they relate to humans, but some North American bat species now have to contend with a disease that has serious implications for their survival. White-nose syndrome (WNS) is a disease caused by the fungus, Pseudogymnoascus destructans (Pd). Ominous right? Among other things, the fungus attacks the skin of the bat while it’s hibernating. This causes the bats to wake up and use valuable fat stores they need in order to survive the winter. First detected in New York in 2006, WNS continues to spread rapidly across North America. USFWS is working together with state and federal agencies, and Tribes to understand the disease, how it spreads through populations, and how we might mitigate its impact on bat populations.  

image

Photo: Looking for closure between the cartilaginous epiphyseal growth plates which differentiates adults (closed) and juveniles (open).  These growth plates are found on long bones in mammals (i.e., humerus, radius, ulna, clavicle, femur, tibia, fibula etc.). Credit: USFWS

The Forest Service and ODFW folks in central Oregon are an amazing bunch of people, and I’m able to go out with them occasionally to mist net bats.  This season’s bat capture effort was part of fall swarming surveys that took place different caves throughout central Oregon. We head out before sunset, set up the nets but keep them closed until we see the first bat fly.  Once we open the nets, the fun begins.  Bats fly into the nets, fall into a pocket, and we carefully extricate them. I received a full round of rabies pre-exposure shots so I could handle bats this season.  Getting them out of the nets seemed like such a daunting task but it’s fairly easy once you figure out what direction they were flying when the hit the net.  Lots of itty bitty bat teeth to avoid.  The bats hang out in little bags until we can process them in the order they were received, and we also swabbed the little dudes and dudettes for Pd.  

image

Photo: Blacklighting wings to look for evidence of WNS.  Generally, bat wings fluoresce orange-yellow under long-wave ultraviolet light if the bats have WNS. The fluorescence corresponds with tiny lesions on the wing membrane, a symptom indicative of WNS. Credit: USFWS

Cool tidbit: bats are the longest-lived mammals relative to their body size.  We captured a banded bat, and I was super curious to find out when and where it was banded.  I sent an email to the Western Bat Working Group and received quite a few responses.  Turns out, the bat with the red band around its forearm was caught and banded at the same location approximately 20 years ago. Since it most likely wasn’t banded as a juvenile it’s possible the bat is older than 20!  Super cool and anecdotally suggests that bats (at least this one) may have high site fidelity.

image

Photo: It’s super hard not to envision the bats singing heavy metal music when you handle them. Credit: USFWS

image

Photo: Set up phase at a cave.  Folks on the right are setting up FLiR (forward-looking infrared) to observe bats entering and exiting the cave.  Folks on the left are setting up the processing station. Credit: USFWS

9 notes

  1. terri104 reblogged this from usfwspacific
  2. kartana reblogged this from usfwspacific
  3. usfwspacific posted this
We make Tumblr themes