What is it about?

Explanations for the phenotypical features resulting from colonization of subterranean environments have always been a source of controversy. Although a great number of cave organisms are blind, they nevertheless display responses to light. The interpretation of this phototactic responsiveness in cave-dwelling animals may provide clues on the general issue of evolution of behavior in parallel with specialized structures. We studied the phototactic responses in two amblyopsid fishes of North America and found responses to light only in the species reported to have a functional pineal organ. Our findings are consistent with the hypotheses that (1) adaptation to the cave environment is a gradual process and (2) responsiveness to light in cave fishes may best be understood as a relict character, one that exists in an environment where it may never be expressed.

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Why is it important?

Because it shows that evolution of fishcake behavior is gradual.


Another example of light responsiveness among cave animals is a relictual character.

Dr. Aldemaro Romero, Jr.
University of Miami

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This page is a summary of: Responses to light in two blind cave fishes (Amblyopsis spelaea and Typhlichthys subterraneus) (Pisces: Amblyopsidae), Environmental Biology of Fishes, October 1997, Springer Science + Business Media,
DOI: 10.1023/a:1007321031997.
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