Wild Things: Life as We Know It
Bumblebees, elephants and endless summer
- Smithsonian magazine, October 2006, Subscribe
Figure 1. Koitogor and the Samburu elephants.
(A) Koitogor Mountain â a prominent feature of the Samburu Landscape rising 300 m above the adjacent plain. (B) Three-dimensional model of Koitogor with individual elephant tracks shown as coloured lines. (C) NDVI image (February 2000) demonstrating that even in the dry season (February 2000) the hill (outlined) is greener than the plains although not the river banks (bottom). (D) Energy calculations for the costs of ascending Koitogor (grey, map topography) for a 100 kg animal (middle) and a 5000 kg elephant (top) with the colour coding indicating the basic cost of ascent from green to red (for details see text and Figure 2 legend, and the Supplemental data). Current Biology
Taking the Low Road
Where do elephants roam? Tracking 54 African elephants equipped with GPS-transmitter collars in northern Kenya, scientists working with the Save the Elephants foundation clearly documented that the animals avoided hills. Why? The scientists calculate that it takes an elephant 25 times more energy to gain, say, 100 feet in altitude than it does to walk 100 feet along a flatland. And since an adult elephant already spends 18 hours a day foraging to fuel a typically 9,000-pound body, mountaineering isn't worth the effort, even if there's food uphill. The new findings may help conservationists secure elephant habitats.
Flight of the Bumblebee
When biologists presented bumblebees with a mixture of artificial blooms—some heated and marked with purple, others slightly cooler and pink—most of the bees returned to the purple ones. The study, from the University of Cambridge and the University of London, is the first to show both that bees prefer warmth and that they learn quickly where to find it. As the researchers point out, a bee can't fly unless its body temperature is at least 86 degrees; landing on a warm flower would help it retain body heat.
Contagious
Researchers at University College London have discovered a unique contagious cancer. The genital tumor, found only in dogs, is not caused by an infectious agent (as some human cancers are) but by the transmission of cancerous cells during sex. The disease, which afflicts dogs worldwide, is rarely lethal. The scientists speculate that the cancer originated in a husky or Shih Tzu from East Asia or Siberia 250 to 2,500 years ago.
Endless Summer
A small seabird has logged the longest annual migration ever recorded. Scientists from the University of California at Santa Cruz attached monitors to 19 sooty shearwaters and found they covered some 39,000 miles over 262 days, tracing "figure eights" across the Pacific (blue, breeding grounds; yellow, northward migration; orange, wintering grounds). Arctic terns fly similarly long routes, but it's not known if they do so within a year.
Observed
Name: Praying mantis
Praying For What? Probably protection, among the males. The females occasionally bite the males' heads off during mating.
Talk About High-Risk Sex: The question has been whether males resist this cannibalism or submit to it, essentially surrendering their lives for the privilege of passing on their genes.
And? The males are love struck but not suicidal, suggests a new study by researchers at the State University of New York at Fredonia. Males approach hungry females (as opposed to well-fed females) more cautiously, court more assiduously and mount from a greater distance. Post-coitus, a male will cling to a hungry female about three times longer—perhaps waiting to seize the moment for a safe dismount.
Subscribe now for more of Smithsonian's coverage on history, science and nature.
| Tweet | Digg |
Comments