Wide or White?

White Rhino

Recently, one of the last four northern white rhinos in the world died in captivity. Now only three members of this endangered species survive.

The efforts to conserve the Northern White Rhino were initially fruitful, but the resurgence of poaching activity has now brought them to the near extinction. These animals are killed for their horns, which are used to make traditional medicines for many major human diseases and also to make decorative articles.

Actually, the white rhino is not really white. It is grey. There is very little difference in the colour of the black rhino and the white rhino. Then why is it called so? The answer to this lies in the more appropriate name of the white rhino: it is also called the square-lipped rhinoceros.

When Dutch settlers in Africa saw this species of rhinoceros, they realized that these had a wider mouth than the other rhinos. So the Dutch called these rhinos ‘wijd rhinos’. ‘Wijd’ in dutch means ‘wide’. However, the English settlers that followed them mistranslated the word ‘Wijd’ word as ‘White’ – hence the name ‘White Rhino’.  

The White rhinos have a wider squared upper lip, which helps them to bite off short grass. The black rhino on the other hand as a pointed upper lip which helps it to bite off leaves from trees.

Another theory about their name says that the white rhinos, although actually grey, appear white because their backs are often covered with white bird droppings.

One male and two female northern white rhinos left in this world are currently kept captive under high security in a conservatory in Kenya, to protect them from poachers.

 

Black Rhino

 References:

1. http://www.iucnredlist.org/details/4185/0 

2. http://animals.nationalgeographic.com/animals/mammals/white-rhinoceros/ 

3. https://www.savetherhino.org/rhino_info/species_of_rhino/white_rhinos/factfile_white_rhino

The story of the horns

Do you recognize this picture? A devil’s head with horns?

No. In fact it is a close-up picture of a seed. What look like horns are actually hooks.

You might wonder what hooks are doing on a seed! These hooks allow the seed th stick to the fur of an animal. When the animal moves from one place to another, it carries the seed along with it. When the seed falls off the animal to the ground, it has travelled a large distance from the parent plant. Like other modes of seed dispersal, animal dispersal of seeds also helps plants to colonize new habitats.

This is just one mode of seed dispersal. A more common mode of animal dispersal of seeds is through animal droppings. Generally frugivores i.e. fruit eating animals consume the seed of the fruit with their fruit meal. They are unable to digest the seed, which is then thrown out of their body through the droppings, at a new location where the animal has reached. This seed germinates where it falls, giving rise to a new plant.

Some animal dispersed seeds are covered with a slimy substance which helps them to stick to the bodies of birds. The birds fly over large distances and carry the seeds along with them.

References: 

1. http://www.britannica.com/topic/animal-dispersal-in-rainforests-1673040

2, http://theseedsite.co.uk/sdanimal.html

3. http://www.webpages.uidaho.edu/range556/appl_behave/projects/seed_dispersal.html

The Wind Tales

I was walking along a crowded road in the middle of the city. Like many of our roads, this road too was lined with huge old trees. Right there on the footpath, I found something that we were fascinated by as children. Many nature enthusiasts fondly call it the ‘monkey biscuit’, since monkeys nibble at it.

This is the seed of a plant called Angsana or Petrocarpus indicus. What makes it special are the wing like papery structures that surround it, and make it ‘fly’. This is one of the many types of seeds that are dispersed by wind. The wind carries these seeds over large distances. If the seed lands on a surface that is suitable for germination, it can grow into a new plant there. 

Angsana seeds

Plants of the genus Shorea have structures similar to blades of a helicopter attached to their small fruits. These plants disperse their entire fruits with the help of the wind. The seeds, of course, are inside the fruit!

Shorea fruits

The Dandelion seeds have feathery bristles around it which help it to float in air like a parachute.

Dandelion seeds

The structure of seeds of Alsomitra macrocarpa inspired the structure of the first gliders.

Alsomitra macrocarpa seed

Dispersal of seeds in this way helps the propagation of the species to distant places. If the offspring of the same plant grew in close proximity with each other, they would have to compete for food, water and space. Dispersal of seeds to faraway places ensures that this problem is solved.

References:

1. http://theseedsite.co.uk/sdwind.html

2. http://waynesword.palomar.edu/plfeb99.htm

Jaws

I read in the newspaper the other day, that a man was arrested for trying to smuggle shark teeth into India. Import of shark teeth is prohibited in the country under the Wild Life Protection  Act of 1972.

But why do people try to smuggle shark teeth? What makes shark teeth so precious?

Shark teeth are not just teeth. They are fossils. Sharks do not have any bones in their body. Their skeleton is made up of a softer tissue called cartilage. When a shark dies, the cartilage decays along with the rest of the body. What remains of dead sharks are only the teeth. These teeth get covered with minerals and sand, and hence do not get corroded. The get fossilized. It takes about 10 000 years for the fossils to get formed.

These fossilized teeth lying on the sea bed often get washed ashore by the waves. They can be spotted by people in the sands at low tide.

During the renaissance period, people mistook these shark teeth for fossilized tongues of dragons and snakes. They were used to cure snake bite. Due to this quality, people considered them lucky, and shark teeth came to used as charms for good luck.

Now that shark teeth have been recognized for what they are, they have become precious commodities and collector’s items. The teeth of the giant pre-historic shark, the Megalodon are the most valuable of all. They can measure upto 7 inches and weigh more than a pound.

Fossilized shark teeth appear brown or blue because of minerals deposited on them. Shark teeth are commonly found on beaches of California. Sharks loose one tooth per week, on an average, while biting off prey. This is because their teeth are not attached to roots like the human teeth. And once a tooth falls off, it is immediately replaced by the one behind it. Yes, sharks have multiple rows of teeth.

Further reading:

1. http://www.enchantedlearning.com/subjects/sharks/anatomy/Teeth.shtml
2. http://www.veniceflorida.com/shark.htm

Noisy Flights

Why is the humming bird called so?

It is because of the humming sound it makes while flying.

Have you ever tried running and singing at the same time? It would be impossible wouldn’t it? You would start panting within no time! Then how does the humming bird manage this?

The secret is that the sound made by this bird during the flight is not vocal at all. It is caused by the rapid beating of its little wings, just like bees and dragon flies. This little bird beats its wings around 60 to 80 times a second!

In fact, the sounds made by the feathers of this bird are not restricted to humming alone. The elaborate courtship displays of humming birds comprise of a bomb dive from a great height. The dive is accompanied by a loud chirp. But this chirp again, is not vocal. During the dive, the bird spreads out its tail feathers, just for 60 milliseconds. The feathers vibrate for this brief period and the air passing across them gives the chirp that attracts the female’s attention.

Humming birds are the smallest vertebrates, the smallest hummingbird, the Bee Hummingbird being no more than 2.25 inches long. These creatures can hover at one place in air for a long period of time. They are capable of flying forwards, backwards, upwards and downwards, an incredible feat that no other bird is capable of! This is possible because they have wings that rotate through 180^o. Unlike most birds that flap their wings back and forth to fly, hummingbirds move their wings in the shape of an eight, so that they can move in any direction. They have strong pectoral muscles that make this possible.

Hummingbirds are mainly found in the American continents. The feed on nectar from flowers, from where they get their sugars. For proteins, they feed on insects.

Further reading:

1.http://birding.about.com/od/birdprofiles/a/whatishummingbird.htm

2.http://www.sciencedaily.com/releases/2012/09/120927091924.htm

3.http://www.sciencedaily.com/releases/2010/11/101121122532.htm

4.http://www.youtube.com/watch?v=l3XT6qoNMMQ

Forests in the sea

Whenever we talk of forests, we visualize a vast expanse of land with lots of large trees and thick lush green undergrowth…..and a variety of big and small animals and insects living in the midst of this vegetation. We may be well aware that there are different types of forests like tropical evergreen forests, coniferous forests of the temperate region, deciduous forests etc..Grasslands are also forests.

But how many of us are aware that there are forests under the sea?

Along the Pacific coasts of the North America, South America, Australia and near South Africa, the ocean beds are densely populated with the Giant Kelp. These are large algae that grow to about 90 feet high. They are brown algae and absorb light using the pigment fucoxanthin which gives them their brown colour. Large numbers of these algae grow close together forming “Kelp forests”.

Kelp grow in waters that are nutrient rich, at a temperature below 21^oC. They grow in shallow waters near the coast so that they receive sufficient sunlight.

Kelp forests are the most diverse marine ecosystems. A variety of invertebrates, fish, marine mammals and birds live in and around these forests. Large creatures like sea lions, seals, otters, or even whales may take shelter in these forests to escape from storms or predators. Kelps are known to calm down sea storms because they weaken the currents and waves. They protect the shore from wave action.

Sea Urchins feed on Kelp to such a large extent that at times they raze the entire forest to ground and prevent it from regrowing. This ecological imbalance is however taken care of if there are enough Sea Otters to prey on the urchins. Thus, the Sea Otter is a keystone species of this ecosystem and prevents it from collapsing.

In today’s times of energy crisis, scientists are trying to use Kelp as a source of renewable energy. They are trying to make fuel from Kelp using bacteria.

Further reading:

1.http://theweek.com/article/index/223581/the-mutant-bacteria-that-turns-seaweed-into-fuelnbsp

2.http://www.csupomona.edu/~biotrek/posters/kelp_anatomy.pdf

3.www.youtube.com/watch?v=ZQb9ZFWfNZE

Fish with a difference

As a habit, I go to the beach for a walk every morning. As dirty as the beach is, we rarely see any sea animals there – except crabs. But this morning, the tide was low, and I ventured far into the water, in the hope of seeing something more. And I did see something……  

A unique little creature. 

The sand was wet, with many little puddles. And in these puddles I could see some animals. They were brown in colour, about three inches long, one inch thick. In water, they would wriggle continuously. Occasionally, one would come out of the puddle, and jump about in the wet sand.

These creatures were none other than the mudskippers. They are amphibious fish. Yes, you got it right – amphibious fish. That means they can live on land as well as in water. These are one of the few species of fish that can survive when out of water.

We are aware that most land animals breathe air through lungs. That is where we get oxygen from. Fish have gills instead of lungs, and through these, they absorb the oxygen dissolved in water. When most fish come out of water, the walls of their gills stick together, so that they can no more breathe. Ultimately they die.

But what sets the mudskipper apart is its ability to breathe when out of water. Like other fish it has got gills too. But around these gills it has large chambers in which it can store water, with a bubble of air, before coming to land. So although the mudskipper is on land, its gills are surrounded by water, so that the walls don’t stick together.

The mudskipper can also breathe through its skin, as long as the skin remains moist. So it has to return to water time and again for a splash. In fact, some mudskippers remain close to water, with their tails always dipped in water. This led some early observers to believe that mudskippers breathe through their tails!

Where does the mudskipper get such a funny name from? Well – when on land, they use their front fins to move about. Both the fins are used together, like a man walking on crutches. They move about in a series of ‘skips’ - hence the name. To attract females, the males may propel themselves into air as high as two feet, with the help of these fins. Some can even stand on their tails!

Next time you visit a beach during low tide, watch out for these little wonders……  

Further reading:

1. http://www.youtube.com/watch?v=KurTiX4FDuQ

2. http://worldfishcenter.org/Naga/Naga25-3&4/pdf/NAGA_25no3n4_features_d.pdf

3. http://free-journal.umm.ac.id/files/file/09_2445_ns0805_79_89.pdf

4. http://www.mudskipper.it/Profile_file/Polgar&Crosa09_online.pdf