Geoscience Reference
In-Depth Information
evicts toxic substances before these are absorbed any further into our bodies, but it
can also be a reaction to severe physical or psychological trauma, or induced artifi-
cially bymanually triggering a “gag reflex” in the back ofthe throat. Inother mam-
mals,eatingrottenfoodordrinkingbadwatercancausevomiting,butitalsocanbe
part of a healthy lifestyle. For instance, cats cough up hair-balls, which are a result
ofdailygrooming,orgrassestheychewedearlier.Nonetheless,asmanypetowners
and trackers know from experience (and shoe cleaning), these excretions are often
placed deliberately, such as at doorway entrances, on sidewalks, or trails used by
other animals. Hence, regurgitated food can serve a dual purpose, similar to that of
urine or feces: keeping digestive tracts healthy, but also sending territorial commu-
niqués to anyone who might be “listening.”
Again, birds are different. Sometimes not all food makes its way through a
bird gut, but instead returns from where it came. Probably the most well known of
such deposits are cough pellets, also known as gastric pellets. Owls and some other
predatorybirdsproducetheseregularly,anditisperfectlynormalandhealthy.Owls
or hawks start these pellets by: grabbing a mouse, chipmunk, or squirrel; eating it
wholeorinchunks,withfur,bones,muscle,andorgansmostlyintact;anddigesting
most of the protein in the proventriculus and gizzard. These birds then eject the un-
digested parts from the proventriculus, all packaged in a neat little cylindrical mass
consisting of fur and bones. For smaller mammals swallowed whole, its entire skel-
eton might be extractable from this pellet.
Gastricpelletsvaryaccordingtothesizeofthebirdturningitsheadandcough-
ing,aswellaswhatitate.Forinstance,Ihaveseencandy-barsizedpelletsmadeby
wading birds, such as herons and egrets; these are filled with fish scales and bones,
or sometimes crayfish parts. For seagulls, their much smaller pellets include lots of
molluscan or crustacean body parts, the latter reflecting bountiful fiddler crabs that
might be living in nearby coastal environments. Tracks associated with these cough
pellets normally show the coughers with their feet together (side by side) and a pel-
let in front of the tracks.
