Wild Things: Life as We Know It

When West Nile virus surged across the United States between 2001 and 2004, infected migratory birds were blamed for the disease’s rapid expansion. Now Johns Hopkins researchers say mosquitoes themselves, which transmit the virus to animals they bite, cover enough ground to carry the virus cross-country. Analyzing DNA from Culex tarsalis mosquitoes from 20 locations in the West, the researchers found that the insects, known to travel up to 2.5 miles per day, interbreed throughout much of the West, mingling more than researchers expected.

Learn more about the culex tarsalis mosquito at the Encyclopedia of Life.

Paleontologists working in Tanzania discovered fossilized bones of a two-million-year-old horned crocodile. Early humans such as Homo habilis lived in the area then, and the 16-foot croc—related to modern Nile crocodiles—would have been the largest predator our ancestors encountered. In fact, the researchers also found fossilized hominid bones from the same site and era. The bones had crocodile bite marks in them. The University of Iowa-led team named the new species Crocodylus anthropophagus. Translation: man-eating crocodile.

Many animals, plants and even bacteria have internal, sunlight-sensitive biological clocks that help them know when to eat and sleep. But now scientists working in Norway say reindeer lack such a clock, a first for mammals: they have no daily fluctuation in melatonin, a hormone crucial for sleep-wake cycles. Reindeer live high in the Arctic, where they experience months of winter darkness and summer light. During these seasons, previous research showed, the animals’ activity is independent of the time of day.

Learn more about reindeer at the Encyclopedia of Life.

In winter, when most vegetation has recoiled into the earth, the plant Helleborus foetidus begins to bloom. How does it stand the cold? Scientists with the Spanish National Research Council found that strains of yeast living in the flowers’ nectar warm the flowers up to 13 degrees Fahrenheit by metabolizing sugars. The yeast allows the plant to flourish even with low temperatures and little sun. The researchers call it a "novel mechanism whereby flowers can raise their temperatures."

Learn more about Helleborus foetidus at the Encyclopedia of Life.

Name: The Asian elephant (Elephas maximus).
Walks: With at least two, and sometimes three, feet on the ground at the same time, according to a new study of the animal’s gait at different speeds.
Runs: Not really, say the researchers, who tested elephants at a conservation center in Thailand by having the animals move at different speeds across a giant platform that measured forces. According to some definitions, a run requires having all feet off the ground at once.
Bounces: Much less than you’d think. Elephants accelerate by taking quicker and longer steps. Since they are always well grounded, they have a smoother stride.

Learn more about Asian elephants at the Encyclopedia of Life.