The dissection of owl pellets
can provide a valuable learning experience for students at
all grade levels. The following guidelines will help to
ensure that this activity is done in a safe fashion.
Owl pellets contain the remains of small animals that the
owl has ingested and can be a source of bacterial
contamination. Carolina’s individually wrapped owl pellets
are heat sterilized at 250º F for 4 hours to eliminate most
bacteria, including salmonella bacteria. We do not treat
them with chemicals. Keep them wrapped until time to use, to
prevent insect infestations or contamination.
A teacher or other adult(s) must oversee
students’ owl pellet dissection activities to ensure that
they perform the activities safely.
Afterwards, promptly dispose of
the owl pellets, plus all disposable materials used in the
activity, and remove them from the classroom.
This is good advice
for any and all lab work involving biological materials. The
students should learn the importance of good laboratory
practices. It will serve them well throughout their academic
career and beyond. Caution in the form of good laboratory
practices is of great importance whenever one is working
with biological materials or chemicals.
Owl pellets
are not to be dissected in school cafeterias or other food
consumption areas. Covering laboratory or classroom tables
with an impermeable, disposable material such as aluminum
foil will greatly diminish the likelihood of microbial
infections. Also use disposable trays, paper, or plates as
work surfaces for dissection of the pellets, and dispose of
them promptly upon completion of the activity.
During the activity, students must
not be allowed to use drinking fountains or get water from
sinks for drinking. Eating and drinking should take place
before the activity or after the student has completed the
activity and thoroughly washed his or her hands, and should
take place outside the dissection area.
Give students disposable gloves and instruct them
in how to use the gloves properly. Students should also be
instructed to keep their hands away from their faces during
the activity, and not to touch other surfaces and items away
from the work surface and materials. Students should be
shown that, when removing gloves, they must avoid skin
contact with the exterior of the glove. Common practice is:
- Remove the first glove
by grasping the cuff, taking care not to touch bare
skin, and peeling the glove off the hand so that the
glove is inside out.
- Remove the second
glove while holding the inside of the first in the
ungloved hand.
- Drop both into the
disposal receptacle.
Immediately after the
activity and after glove removal and disposal, students must
thoroughly wash their hands with soap and warm water,
rubbing them with lather for at least 20 seconds before
rinsing (as recommended by the U.S. Centers for Disease
Control and Prevention—see
http://www.cdc.gov/cleanhands), and should dry them
with clean paper towels. Be sure sinks are available and
well stocked with soap and paper towels. A good
antimicrobial foaming skin cleanser for use with water is
BactoShield® by Steris. A
waterless hand sanitizer can also be a very effective
antimicrobial agent if it is comprised of at least 70%
alcohol. This can be used in addition to hand washing or, if
soap and water are simply not available, in lieu of hand
washing (though hand washing is preferable). Do not use a
waterless hand sanitizer that does not have this high
alcohol content.
Owl pellet dissection
provides a good opportunity to teach skills that will serve
students well in their academic careers and, for some, in
their professional careers or in volunteer activities. They
can learn the importance of, and how to use, personal
protective equipment (gloves in this instance) and how to
protect themselves from microbial infections.
Note: Latex gloves
can cause allergic reactions in some individuals. Carolina
recommends disposable vinyl exam gloves (such as Carolina’s
items
706348,
706349, or
706350), or, for this activity
with sterilized owl pellets, polyethylene gloves may be used
(such as Carolina’s items
706345,
706346, or
706347).
Allow students to use only the tools provided; do not allow
them to use pencils or other personal items that they will
maintain in their possession after the activity. If
possible, use disposable dissection tools and then throw
them away. Otherwise, immediately sanitize tools using a
bactericidal and virucidal cleaning agent according to its
instructions, or by soaking the tools for 2 hours in a 10%
household bleach solution or in 70% ethanol.
Use
a cleaning agent that is bactericidal and virucidal, and use
according to label instructions. Alternatively, 70% ethanol
may be used (be aware that it is flammable), or a 10%
household bleach solution makes an effective sanitizing
solution (be aware that chlorine bleach is corrosive and
irritating to skin and may damage clothing). Use disposable
paper towels and throw them away. Do not use sponges or rags
that might hold and spread bacteria or viruses. After the
students have washed their hands, sanitize the sinks and
surrounding surfaces.
Through this
investigation students learn about the food chain and the
diets of owls. This activity also provides an opportunity to
learn about safe laboratory practices and the importance of
taking precautions. We want to reiterate that the owl
pellets sold by Carolina have been heat sterilized. This
would be expected to eliminate the risk of microbial
infections such as salmonellosis. Just as is always advised
when working with microbes in the lab, though, we need to
assume that owl pellets could be infectious. We need to use
good and prudent safety practices to minimize the
possibility of any sort of microbial infection. Using
sterilized owl pellets and enforcing safe practices make owl
pellet dissection a safe and rewarding activity.