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Wild Things: Life as We Know ItExplore more photos from the story |
Gunning For A Fight
Two chicks hatch; only one will survive. Nazca boobies on the Galápagos Islands often lay two eggs, but there's rarely enough food for two nestlings. The birds avoid this problem with a fight to the death soon after birth. Now a study led by Wake Forest University reveals what prepares chicks for battle: high levels of testosterone and other hormones that promote aggression.
A Sideways Glance
Even Darwin floundered to explain flatfish like sole and halibut. Sure, having both eyes on the same side of your head is helpful if you lie on the ocean floor, but how does such a strange gaze evolve? Fossils from 50 million years ago, newly analyzed by a University of Chicago researcher, show that a flatfish ancestor had one eye in a normal position and one near the top of its head, a transition to its modern form.
Observed
Name: Agamid lizards living in Australia.
Walk: On all fours.
Run: On their hindquarters, at least in some species.
Confound: Attempts to ascertain why, in evolutionary terms.
Submit To: Treadmill running and high-speed video recording.
Which Yield: Data suggesting that species that run bipedally do so because they are...popping wheelies. Species with heavy hindquarters are most susceptible to having their front quarters lift off the ground during rapid acceleration, according to researchers in Australia. No evolutionary advantage was evident.
Floral Flirtation
Flowers sway in the breeze to beckon pollinators, a study from Wales' Aberystwyth University suggests. Sea campion plants
with slim stems fluttered the most and attracted the most insects. (Flowers with average stems set the most seeds though, apparently because pollinators visited more stable flowers longer.) The study is the first evidence that "waviness," like color and scent, influences a flower's attractiveness.
Time to Get Cracking
The sound that Nile crocodile embryos make shortly before hatching is not just baby talk. Scientists in France played recordings of the "umph! umph!" calls to croc mothers and egged siblings; the moms dug up their nests and the babies got cracking. Synchronized hatching may minimize the nest's exposure to predators.
Additional Sources
"Perinatal Androgens and Adult Behavior Vary with Nestling Social System in Siblicidal Boobies," Martina S. Müller et al., PLOS One, June 2008
"The evolutionary origin of flatfish asymmetry," Matt Friedman, Nature, July 10, 200
"Why go bipedal? Locomotion and morphology in Australian agamid lizards," Christofer J. Clemente et al., The Journal of Experimental Biology, July 1, 2008
"Do flowers wave to attract pollinators? A case study with Silene maritima," J. Warren and P. James, Journal of Evolutionary Biology, July 2008
"Crocodile egg sounds signal hatching time," Amélie L. Vergne and Nicolas Mathevon, Current Biology, June 24, 2008
Comments
i love your article so much. i learned many things. i also watched lizrd video
Posted by Sean on September 16,2008 | 09:54 AM
I am curious about hindleg running in lizards. I have heard that the function of the lungs is impaired by fast running in reptiles due to the way that the limbs are attached to the body and the overall motion of movement. This supposedly prevents lizards (and any reptile) from sustaining high speed runs. Perhaps hindlimb running helps to reduce this problem and allow for more efficient breathing to prolong high speed runs. Can you please ask the scientists about this and if they have pursued this line of thought?
Posted by Patti Nicoll on May 28,2009 | 02:30 PM