Means vs. Ends

Alright, the article for this week covers two subjects. The first is, you guessed it, iguanas. Specifically, general iguana ecology (was that an oxymoron?). It covers temperature preference, nesting and feeding habits. The second issue is an ethical one. 

Iguana body temperatures ranged from 34.0 degrees to 37.2 degrees Celsius (Hirth, 1963). This is 93.2 degrees to 98.96 degrees Fahrenheit, which is surprisingly not that far from human body temperatures. The air that they tended to reside in was 28 degrees C (82.4 F) to 32 C (89.6 F). Larger iguanas tended to rest in trees, while younger and smaller iguanas rested on the beach and none of the iguanas were ever far from the river or some other source of water. The scientists in the study believed this all had to do with thermoregulation. The water was a quick way for iguanas to cool down while the tree canopy offered heavy insulation, preventing loss of body heat. Remember that iguanas are cold blooded and hence cannot regulate their body temperature thus many of their adaptive behavior relates to thermoregulation.

Iguanas are herbivores, as mentioned before, surviving mainly on leaves and fruits. It has been found that young iguanas may feed on insects, however. As far as nesting goes, iguanas lay eggs in early spring, the most arid part of the year. The eggs are laid on the beach in spots that it takes the female iguanas some time to find. The scientists were not clear on what exactly the female iguanas were looking for, only that they searched for a significant amount of time to find a nesting site. 

As cool as all this iguana stuff is, the most interesting part of the article for me was the techniques used. In order to determine the body temperatures of the iguanas, the lizards were shot with .22 caliber rifle and then their temperature as well as the temperature of the surrounding area was taken as soon as possible. This seems a little ... out of line to me. The study was published in 1963, a time during which animal cruelty standards may have been different, but I'm not sure whether what was gained justified the shootings. Food for thought. 

AA

Hirth, Harold F. "Some Aspects of the Natural History of Iguana iguana on a Tropical Strand." Ecology (1963) 44.3: 613-615. Web. 11 Mar 2012.