Saturday, May 19, 2012

Those Scary-looking Anglerfish With the Big Teeth are Female

Public Domain Image (PD-1923) via Wikimedia Commons
This deep sea fish may be familiar due to its appearance in Finding Nemo, as well as its appearance on almost every list of "the world's ugliest animals." However, you're not likely to see one in person. Seeing a male deep sea anglerfish would be even less likely, and if you did see one, you probably wouldn't know it. When it comes to the humpback anglerfish (the kind in the above drawing) and "sea devils," the fishing lure and huge mouth full of teeth belong only to the females.

You may wonder where the males are. Well, you'll usually find them connected to the body of the female. When a male angler becomes sexually mature, his digestive system stops working. His options are then to either die of starvation, or find a female and join with her as a parasite. Neither option is a great one for the poor male. When he finds a female, he bites her, and then his mouth dissolves into her body. Their blood vessels merge, and over time, the male's organs are absorbed until the only things left of him are his gonads. The female can then use them when she wants to spawn, and she can end up with up to six "males" attached to her.

As far as the lure and giant teeth: the female uses her lure like a human angler would - to draw her prey (other fish) close enough for her to snatch with those teeth. The teeth are angled inward to help keep the prey from escaping, and her jaw and body are pliable enough to allow her to eat prey twice her size.

(Apologies for the lack of updates lately. My classes are starting to take up most of my time. I'll post again soon... I promise!)

Thursday, May 17, 2012

The Blue-Footed Booby Has Multipurpose Feet

Sula nebouxii - 06
Photo Credit: Maros (via Wikimedia Commons)
The Blue-Footed Booby is a bird with feet that are made for more than just walking. Like most seabirds, his feet are webbed and work as paddles for swimming and diving. On the downside, the web shape makes the bird clumsy as he walks on land, which is where his funny name came from ("booby" comes from the Spanish word "bobo," which means "stupid" or "clown"). Even so, the male blue-footed booby is quite proud of his feet, and he uses them to help attract a mate.

As one may guess from this bird's name, the feet are often blue in color. However, the color actually ranges from bright green to dull blue. When the male is ready to attract a female, he will perform a courtship dance full of struts and high steps - all moves meant to show off his feet. Studies have shown that females tend to prefer bright green, and that the color is dependent on the amount of carotenoids in the diet. Therefore, it seems the color is an indicator of the booby's nutritional condition (and suitability as a mate). 

The blue-footed booby has one more important use for those feet. These birds do not have brood patches (a bare patch of skin on the bird's belly for sitting on the eggs), so they use their feet to keep the eggs warm. The parents will continue using their feet to keep the babies warm even after hatching, as the chicks are unable to control their own temperatures for about the first month of life. 

Tuesday, May 15, 2012

A Cheetah's Speed Has a Downside

Gepardjagt1 (Acinonyx jubatus)
Photo Credit: Marlene Thyssen (via Wikimedia Commons)
We all know the cheetah is one fast cat. They can go from 0 to 60 miles per hour in a little over 3 seconds, and can reach speeds of 70 miles per hour, making the cheetah the fastest land animal. Watch a cheetah run and you can't help but be impressed. Their stride can be as long as 25 feet, and at top speed, they can make 3 strides per second. Unfortunately, this amazing speed has a downside for the cheetah.

A cheetah is literally built for speed - their bodies are aerodynamic in shape, they have huge hearts for pumping lots of blood, large lungs and nostrils, a flexible spine, and a long tail that can act as a rudder and counterweight to keep the cat steady as he runs and turns. This sounds great for the cheetah, but it turns out that running is practically the only survival skill he has.

The cheetah weighs an average of 125 pounds, which is small for a big cat. When the cheetah runs at top speed (which he can only do in a short burst), the heart pumps so hard and the body becomes so hot that brain damage can occur if the cat doesn't rest before eating. During the rest period, other predators or scavengers can come in and steal the prey, and there's nothing the cheetah can do about it. The cat is exhausted, and due to his aerodynamic shape, he doesn't have the muscle mass or strong jaws and teeth needed to fight back. All he can do is run.

Some people believe the overspecialization is part of why the cheetah is endangered, but most researchers believe the primary issue is the usual human created problem of habitat loss, along with loss of genetic variation. Fortunately, groups such as the Cheetah Conservation Fund are working to make sure this beautiful cat survives. 

Sunday, May 13, 2012

Elephants Make Great Mothers (and Grandmas, Aunts, Sisters and Cousins)

African Bush Elephants
Photo Credit: Gorgo (via Wikimedia Commons)
Yesterday, we talked about how alligators are great moms. On Mother's Day, we'll talk about another great mom from the animal kingdom - the elephant.

Female elephants have a complex social structure which is centered around the raising of offspring. When a young female reaches the age of around thirteen, she'll go into her first estrus. In other words, she'll be "in heat." This phase only lasts a few days, and will be one of the only times an adult male elephant is involved in a herd (males are usually solitary once they come of age). After mating, the female will carry the baby for 20 - 22 months. When the mother goes into labor, the entire herd will surround her and stand guard while she gives birth to a 150 - 220 pound calf. The herd will then greet the newborn, who is born practically blind and with few survival instincts.

Over the next two years, the calf will be dependent on her mother for food. She will survive completely on her mother's milk for the first few months of her life, and will drink about 10 quarts (about 9.5 liters) every day, which is enough for her to gain 30 pounds a week. The calf will start eating on her own at around age two, but mother's milk will still be a part of her diet.

The mother isn't the only one who takes care of the baby. The rest of the herd, which will consist primarily of related females (with some male calves) will aid in protection, teaching survival skills, helping out if the baby falls or gets stuck, and so on. 

If the calf is a female, she will remain with the herd once she becomes an adult (if the herd becomes too large, some of the elder females will break off and start their own herd). If the calf is male, he will head out on his own at around the age of sixteen.

Happy Mother's Day!

Saturday, May 12, 2012

Female Alligators are Great Mothers

Alligator Baby
Photo Credit: William Stamps Howard (via Wikimedia Commons)
When we think of animals that are good parents, reptiles usually don't come to mind. We tend to think that reptiles aren't very maternal - that they lay their eggs and move on with their lives. However, alligator mothers are some of the best moms around! (With babies as cute as the ones in the picture, how can they not be?)

A female alligator will begin breeding when she is between 7 and 12 years old. Males and females come together to mate in spring, and once the deed is done, the female will search for a place to build a nest. She will gather reeds and other plants to create the mound shaped nest, which will be about 3 - 3.5  feet tall and 7 feet wide. Then she'll lay between 20 and 60 eggs and will cover them up. She'll let the heat from the vegetation in the nest keep the eggs warm (being huge and cold-blooded, she doesn't sit on the eggs to warm them with her body like a bird would). 

The mom remains on guard near the nest for a little over two months while the eggs incubate. The babies chirp as they hatch, and when the mom hears the sound, she'll uncover the nest. If any babies are having difficulty hatching, mom will gently roll the egg in her mouth to crack it. Once all babies are out, mom will carry them in her mouth to the water, where they'll gather together in a pod. 

Baby alligators can hunt and swim, but they are too small to defend themselves from predators such as raccoons, snakes, raptors and herons. The mom will use her powerful jaws and huge body to protect as many of her babies as she can, and the family stays together for at least a year (sometimes two).

Friday, May 11, 2012

Dolphins Vocalize Through Their Noses

Bottlenose Dolphin KSC04pd0178
Photo Credit: NASA (Public Domain image, via Wikimedia Commons)
Dolphins always seem to have their mouths open when they chatter and whistle, so it's easy to assume the sounds are coming from their throats. However, unlike most other animals, dolphins do not have vocal cords. For a long time, scientists believed dolphins produced sounds from the blowhole, but now it looks like dolphin sounds come from their nasal cavities! 

Dolphins produce different sounds such as squeaks, moans, trills, grunts, and so on. They're most famous for their whistles, and they even have what we call "signature whistles" that they use to identify each other. These whistle sounds were a mystery to researchers for a long time, because dolphins are able to produce the sounds underwater, and a true whistle is produced by a stream of forced air. There's also the fact that there's compression when a dolphin dives, which should change the frequency of the sound, but the frequency remains the same.

Last year, researcher Peter Madsen and his colleagues at the Institute of Bioscience in Denmark re-examined a study from the 1970s in which scientists had dolphins breathe heliox (a mixture of helium and oxygen) because it should have mimicked the conditions during a dive by causing a change in frequency. However, the whistles were the same, whether the dolphin was breathing heliox or regular air. Madsen's group concluded that dolphins probably make the whistling sounds by vibrating tissues called "phonic lips" that are located in their nasal cavities. Dolphins can quickly change the frequencies of the sounds by changing the tension of the tissue and the airflow. They can whistle and click at the same time because they have two sets of "phonic lips" that can either work independently or together. 

Tuesday, May 8, 2012

The Gentoo Penguin is the Fastest Penguin in the World

Gentoo Penguin Swimming
Photo Credit: Priya Venkatesh (via Wikimedia Commons)
We've all watched penguins swim at zoos and aquariums (or at least on television). Their movements seem effortless as they glide through the water, occasionally diving, and occasionally leaping above the surface for a breath of air. The fastest swimming penguin, the Gentoo Penguin, can reach speeds of 36 kilometers per hour (that's a little over 22 miles an hour for those of us who live in the USA), thanks to their streamlined bodies and strong flippers. 

The Gentoo penguin lives on the islands surrounding Antarctica and the Antarctic Peninsula (and with Mr. Popper of Mr. Popper's Penguins). Even though they're adapted to living in cold climates, they prefer areas without much ice. They mainly eat krill, squid and other crustaceans, but will also eat fish. 

The adult birds hunt all day long and occasionally venture out about 26 kilometers (16 miles). Because of their ability to hold their breath for seven minutes, they can dive up to 200 meters (655 feet) while chasing after something to eat. They are most vulnerable to predators such as seals, sea lions and orcas while out hunting, so they usually remain close to the shore. When they're on land, the adults only need to worry about humans who sometimes hunt them for their skin and oil. Birds of prey will sometimes dine on penguin chicks and eggs.

This species of penguin is doing well on the Antarctic Peninsula, but populations are dropping on the islands. They are now classified as a Near Threatened species on the IUCN Red List of Threatened Species.

(Apologies for the lack of updates the past few days).

Thursday, May 3, 2012

There Are Vulture Restaurants in India, Nepal, and Pakistan

Photo Credit: Petra Karstedt (via Wikimedia Commons)
If you ever take a trip to India, Nepal, or Pakistan, you can visit a "vulture restaurant." No, a vulture restaurant isn't a place where those who enjoy adventurous eating can sample vulture curry. It's a place where the critically endangered White-rumped and Slender-billed vultures can fill up on safe meat.

Twenty years ago, populations of these vultures were doing fine. There were 50,000 nesting pairs of the two types of vultures in Nepal alone. The numbers have since dropped sharply, and now there are only around 500 pairs. Hem Sagar Baral of the Nepalese Ornithological Union said that if things don't improve, both species could be extinct in ten years.

It's believed that the decline is partially due to habitat loss (a reason we see over and over again when animals become endangered), and partially due to a drug called diclofenac that is often used to treat inflammation in cattle. While generally safe for the cattle, this medication is deadly to vultures. If a vulture eats the meat of an animal that had been treated with diclofenac, he can go into kidney failure, which ultimately ends in death. The drug has since been banned and a different anti-inflammatory drug that is safe for vultures (meloxicam) is being produced. However, some people still use diclofenac for their animals.

A few years ago, Bird Conservation Nepal had a great idea - to open up "restaurants" for the vultures! The idea slowly caught on, and now there are a handful of feeding stations and plans for more. So far, the stations have been successful, for many villagers as well as the birds. Authorities pay villagers for their dead diclofenac-free cattle, and the restaurants draw paying tourists. As far as the vultures, the number of nesting pairs near the Pithauli station has grown from 17 to 46. A captive breeding program has also been started in the Chitwan National Park, so it looks like there's a good chance for a comeback!

Wednesday, May 2, 2012

The Fennec Fox is the Smallest Canid in the World

Fennec Fox
Photo Credit: Yvonne N. (via Wikimedia Commons)
The Fennec Fox one of the cutest animals in the world, and is also the smallest species of canid (the family of mammals that includes dogs, wolves, foxes, jackals, and other dog-like animals). These little guys are even smaller than most of the dogs some celebrities like to carry around in purses. Your average Chihuahua weighs 3 - 6 pounds, and the fennec fox weighs in at 1.5 - 3.5 pounds. The fox's height and length are similar to those of the Chihuahua, but much of their size is taken up by ears and tail. The tail is 7 - 12 inches long, and the ears are about 6 inches each!

Fennec foxes are native to the Sahara desert and other parts of northern Africa. Living in the desert, they need a way to keep cool, and that's what the gigantic ears are for. There are lots of blood vessels near the skin of those ears, which help radiate body heat. Their light colored fur reflects the heat of the sun and protects the fox's skin, and it also keeps them warm during the cold desert nights.

Five more Fennec fox facts: 
- Like many desert animals, they can live for long periods of time without drinking water (they survive from the moisture in their food).
- Their diet consists mainly of insects, but they also eat rodents, lizards, and plant matter.
- They have fuzzy feet to help them walk on the hot sand.
- When temperatures rise above 35 degrees Celsius (95 Fahrenheit), the foxes may start to pant. When panting, their respiratory rate rises from 23 breaths per minute to 690 breaths per minute.
- The "copulation tie" has been known to last two hours and forty-five minutes!