Programming Computer Vision with Python

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The animal on the cover of Programming Computer Vision with Python is a bullhead.

Often referred to as “bullhead catfish,” members of the genus Ameiurus come in three common types: the black bullhead (Ameiurus melas), the yellow bullhead (Ameiurus natalis), and the brown bullhead (Ameiurus nebulosus). These stubborn fish prefer aging, warm-water lakes and are typically found east of the North American continental divide.

Bullheads are known for their obstinacy and tenacity (in fact, people possessing these traits are often characterized as “bullheaded”), and these characteristics have helped them outlive many other species of fish. They can tolerate brackish water and low oxygen and high carbon dioxide levels, making them more resistant to pollutants than most other fish and therefore ideal for lab and medical experiments.

Bullheads are bottom-feeders, prowling in schools at night, on the hunt for clams, insects, leeches, small fish, crayfish, and algae. While doing so, they tend to stir up the bottom of the body of water and destroy aquatic vegetation, which eliminates cover for other species. This, along with their high reproductive rate and subsequent overpopulation, can make them somewhat of a curse for fisheries. For this reason, restrictions are rarely placed on bullhead fishing.

All three types of bullhead are scaleless and average 8 to 10 inches in length. The whisker-like barbells, or feelers, at the corners of their mouth and in a line on the lower chin give them ...