Day 164: As much as I love the froggy folk, I find it difficult to say anything nice about Rana catesbeiana, the Bullfrog which is outcompeting native frogs in a rapidly growing number of ponds and wetlands in the Pacific Northwest. This exotic ("non-native") species is easily identified by its large tympanum (eardrum), as large or larger than the eye. Color can be quite variable, brown to brownish-green, green, or in some cases, even blue. In size, Bullfrogs can measure up to 150 mm. from snout to vent. The female is capable of laying up to 6000 eggs in a single season. Native to the eastern portion of the US, Rana catesbeiana is considered a problematic invasive in Washington.
Maybe it's just naturalist lingo and has its own weight and significance but I'm always amused by talk of non-native species--who determines that? When does one become a native? And given the nature of the ebb and flow of life what does it really mean to be a native?
ReplyDeleteFunny you should mention that. I have raised the same question on many occasions. If a species is migratory and happens to migrate into new territory, isn't that part of its evolution? However, in the case of Bullfrogs in Washington, there is evidence that they were introduced via a human agent into a Thurston County lake where they bred prodigiously and then spread to other waters. The human factor crops up in the background of most invasives. I suppose an argument could be made for humans' proclivity for transporting familiar things to new locations also being a natural process, but I think that's stretching it just a bit.
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