Stickiness of Gecko's Feet

Everybody knows that gecko’s have sticky feet. This is one of the coolest facts about them. They are able to stick and attack or cling to a surface no matter how smooth and unstuck as many times as they want to without loosing their stickiness. This is because their feet are coated in setae. These are microscopic hairs in the shape of a spatula. The reason that their stick never runs out is because the setae clean themselves. This is all done without the use of any fluid adhesives, which Kellar Autumn discovered in 2002. Now, new research from Autumn is showing us that geckos’ feet can be even sticker when they are in a humid environment. They are able to stick to surfaces better because of microscopic water droplets in between the setae and the surface they are attaching to. Capillary action causes the water to adhere to the setae, in turn, softening their feet. This is why the humid environment around geckos can cause a stickier surface on their feet. In his research, Autumn and his fellow scientists gathered samples of the setae and imitated their movement with a “robotoe” machine so it was as it would be on a live gecko. As they tested this in different environments, at different speeds and with different surfaces to attach to, they still couldn’t figure out why humidity increases the stickiness of the setae. It was a graduate student, Michael Proswe, who finally thought he saw a cause of this increase. He realized that the substance that makes up setae, keratain, gets softer in humid environments, he thought to measure the softness of the setae in different conditions. Another scientist, Jonathan Puthoff, then proved using a mathematical model that softness is related to the stickiness of the setae. This showed that instead of what Kellar had predicted, the increased attachment to surfaces was caused by an increase in softness in the setae.

The video below talks about how the setae on gecko's feet work.

The Diseased La Loma Tree Frog - Extinction or Not

More and more frogs are becoming extinct around the world every day while other frogs are continuously added to the extensive lists of endangered species. One of these species is a tree frog called the La Loma tree frog or Hyloscirtus Colymba. One of the most prominent causes of this is a new disease known as chytridiomycosis, which is rapidly spreading throughout this species of frog. Thankfully, the La Loma tree frog may not become extinct yet because of some as successful scientists in Panama. The Panama Amphibian Rescue and Conservation Project (PARCP) recently began breeding this frog despite being tough to care for when raised in captivity. Not a lot of information was known about the care of these frogs so it was difficult to do this but after many attempts, these biologists have succeeded. One biologist that worked with these scientists on the project was Brian Gratwicke from the Smithsonian National Zoo. He used his extensive knowledge of amphibians to work with them to learn about the care of this frog. At the moment there are 28 La Loma frogs residing at the Summit Municipal Park near Panama City along with four tadpoles. These animals are constantly monitored for details of care for future breeding. Breeding is not the only effort being made by the biologists in Panama; they also hope to find a cure to this disease so that they may one day release these frogs into the wild but for now they will keep them protected. These scientists are doing their best to save as many species of frogs as they can and they aim to breed at leas 20 additional frog species in Panama. This will make a small but important dent in the 33% of amphibians in the world that are endangered. The information gained by these scientists will also help to breed and in the end save many other important forest animals from extinction.

You can also check out this cool Prezi about a La Loma tree frog named Phillip.

The La Loma Tree Frog on Prezi

 Here is a video with Brian Gatwicke about his work with amphibian conservation.

Osmoregulation in Marine Iguanas

Marine iguanas like the one to the right often live in the Galapagos Islands spending much of their time in a marine environment.  They therefore are hypertonic to their surroundings so when they consume salt water, they have too high a concentration of salt inside them.  They also gain salt through their main food source, algae in seaweed.   They need isotonic conditions where they have the right concentration of each substance. Unlike some animals they cannot produce a concentrated urine containing salt to let them conserve water and relieve them of all the sodium chloride inside them.  Instead they have adapted to their environment allowing them to regulate the high concentrations of salt.  The primary adaptation that lets them do this involves glads at the top of their heads, above their eyes and noses.  These glands excrete sodium chloride decreasing the concentration of it inside them and releasing salt into the outside environment.  Another gland sorts the salt from the food and water consumed by the iguanas and sends it to the excretion gland.  When they "sneeze" out the salt through their glands, it often lands on the end of their snouts and dries there forming a gross white crust.  This salt sneezing allows marine iguanas to eat and drink what they do without gathering a high sodium chloride concentration inside their bodies.  This regulatory adaptation is what allows them to live in a marine environment because without these excretion glands, a high concentration of salt would build up in the iguanas bodies causing them troubles and maybe even bringing about death.

Below, there are several videos showing marine iguanas using the excretion glands to get rid of salt. 







Research Sites:
- http://www.encyclopedia.com/doc/1G2-3400700323.html
- http://www.cartage.org.lb/en/themes/sciences/zoology/animalphysiology/osmoregulation/osmoregulation.htm
- http://en.wikipedia.org/wiki/Marine_iguanas
- http://www.geo.cornell.edu/geology/GalapagosWWW/MarineIguanas.html