A Little Bit More
Catfish are one of the freshwater fisherman’s most popular quarry. The three different kinds of Bullheads (Brown, Yellow, and Black) are just three kinds of catfish and probably the best known – at least in fishing circles, but there are other kinds too. Bullheads are plentiful, easy to catch, and provide excellent eating.
Handling any fish is difficult enough with its slippery body, but all of the catfish increase this difficulty with spines that can inflict a painful jab. When a catfish goes into its “defensive mode” it spreads its pectoral and dorsal fins so they’re at right angles to its body. Any unwary fisherman, or predator for that matter, that isn’t careful is likely to be stuck by one of these spines as the fish squirms and wriggles. Although many North American freshwater fishes have spiny fins, only the catfish has such specialized spines with an irritating mucous covering.
The 8 barbels or “whiskers” on a catfish are an obvious characteristic of the family. These structures are totally harmless and serve as highly sensitive feelers for taste and smell. Since many catfish live in muddy waters or feed at night, the barbels make them the aquatic bloodhounds of their environment.
The 6 different species of madtoms are close relatives of the larger catfishes, and go one step farther with venom glands at the base of their spines that can produce a much more painful, long-lasting “sting”. Madtoms, unlike the larger catfishes, are found in small, clear, rocky streams, and are too small to interest fishermen so are not at all well known by the general public. But, whether you’re handling the larger catfishes or the smaller madtoms, you’ll want to be sure to handle with care!
Activities
Science – On the Defensive
Objectives: Better understanding of defensive mechanisms
Materials: Access to library or internet
Catfish are not the only animals that have special defenses. Many kinds of animals have various ways to deter predation. I’ve listed some that have an assortment of different ways to reduce their chances of becoming some animal’s dinner. You may want to share this list with students and see if they can figure out what the “defenses” are for each of the following:
- Stink Bugs: can emit a bad-smelling substance
- Rattlesnakes: able to inject venom with fangs
- Newts: have a mucous secretion that is a strong irritant
- Box Turtles: hard shell that can enclose entire body
- Snapping Turtles: strong, sharp jaws
- Toads: glands on back that give off toxic material
- Bombardier Beetle: can eject liquid that burns
- Black Widow Spider: especially toxic bite
- Scorpions: stinger
- Wasp and bees: stingers
- Crayfish: pinch with their claws
- Jellyfish: stinging tentacles
Key Concepts
Structures and Functions, Identification, Adaptations and Diversity
Questions
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