Skulls
This activity will take a lot
of effort to get ready to go, but the results will be valuable for many
years. I have a collection of over 40
different animal skulls, twenty of which I share with campers during the
summer. I obtained my initial collection
by picking up road kill and simply letting the skin rot off in a cage in my
back yard. Others may prefer boiling or Dermestid beetles.
In
Using these skulls, one can
easily lead children through the detective work that it takes to identify a
skull. Skulls also provide an impetus
for thinking about animal's diets based on their dental adaptations. The discussion of adaptations helps campers
to appreciate the complex and wonderful ways in which God has provided for each
organism in order to fulfill its needs.
Begin the session by
discussing the four different kinds of teeth: incisors, canines, premolars, and
molars. Incisors work basically like
scissors (demonstrate with scissors) and animals use them mainly to cut pieces
off of larger food items. Ask the
campers what they use their front teeth for, and draw the conclusion that
incisors are particularly important for animals that eat plants. Canines work like knives and are specialized
for ripping and tearing, especially the flesh of other animals. One can infer that animals with
well-developed canines are meat eaters (carnivores). Premolars and molars are difficult to
distinguish from each other, because both are used for grinding food material,
working like a mortar and pestle.
Premolars generally have only one cusp (indentation on the top surface)
whereas molars have two; molars are also further back than premolars. Animals with virtually flat molars eat lots
of plants and animals with relatively sharp molars eat meat.
Skulls can be identified by
the number of each kind of tooth, counted on only one side of the skull. We count only one side of the skull because
the other side is identical. I illustrate
the half a head concept to campers through a raccoon skull cut in half and
mounted on plexiglass. I also introduce the dental formula on this
example by having the number of incisors, canines, premolars, and molars
counted and labeled. A dental formula
works as follows: I 3/3, C1/1, Pm 4/4, M2/2 which means that the organism has
three incisors on top and three on bottom, one canine top and one bottom and so
on. Along with discussing the dental
formula, I also remind them that simply counting the total number of teeth can
be a valuable beginning point. For
example, opossums have a distinctive number of teeth. If I were to count 50 teeth
in a skull (25 in a half skull), I could identify it quickly as an opossum.
Next, hand
out skulls to all the campers or perhaps pairs of campers, as well as detective
guides containing a variety of skull formulas on them. Ask the campers to identify their animals and
try to guess what the animal might eat.
Give the campers time to work on the problem, as even older campers find
this a challenging activity. Help them
to count teeth that have fallen out and reemphasize the half a head
concept. Have campers present their
identification to you before having them share about their animal to the entire
group.
As the children present, draw
attention to the particular adaptations in each skull. For example, foxes have an extended snout, deer entirely lack canine teeth and upper incisors,
and so on. This stage will depend on
your own knowledge of your own collection, which you can develop through a
variety of sources. Emphasize the
uniqueness of each organism and how well it corresponds to its survival
needs. Since God helps these animals to
survive in their different situations, how much more does God know our situations
and can provide for us in any circumstance we may find ourselves.
To build your own knowledge of skulls, I recommend the following resources: