The second kind of defence is very obvious. It is to carry armour and/or offensive weapons like horns. These are permanent visible defences. For larger prey animals this can be effective if linked to another defence. Thus, in natural habitats, elephants have tusks, and they also have huge size. Antelope have horns, and can also run fast. Almost all large herbivores live in herds, which undoubtedly is safer than living alone.
These work when a predator detects a prey, or when a prey notices a predator. The function of secondary defences is to increase the chance of the prey surviving the encounter (meeting).
Everything costs something. All defences incur costs. For survival, an animals needs food, and needs to stay alive to reproduce. Energy and time spent on defence can be considerable, but justified if it makes reproduction more likely. There are these kinds of costs:
Boomtown
A boomtown is a place that has very quick population and economic growth. Boomtowns are usually mining towns where an important mineral resource such as gold, silver, or petroleum has been found. It can happen, for example in a gold rush. Gold rush towns usually shrink and disappear after the gold is dug up. They become ghost towns.
The word can also be used for places that grow for other reasons. This can be the town being near a major city, in a nice climate or near a popular attraction.
Alexander (movie)
Alexander is a 2004 epic drama war movie about Alexander III of Macedon. It was directed by Oliver Stone.
The budget of this movie was about 155 million dollars. Its box office was about 167 million dollars.
The story is about Alexander III of Macedon and his battles against Great Persian Empire and his victories, in the beginning, movie shows early life of Alexander and what happened in his young ages and what his father King Philip II did. When Philip died Alexander was King of Macedon and decided to fight with Persian Empire and at last he conquered Persia. When he wanted conquer India in a battle he wounded and died.
Karaj
Karaj (Persian: کرج) is an Iranian city and main city of Alborz province. The city has about 1,370,000 inhabitants.
Karaj is 6th largest city of Iran.
Plymouth, Montserrat
Plymouth was a town in Montserrat. It was founded in the 1700s and named for Plymouth, England. It served as the capital of Montserrat. It was also the island's main port. It was destroyed by a volcano in 1997.
Cognitive bias
A cognitive bias happens when someone makes a bad choice that they think is a good choice. This bias is an important part of the study of cognitive psychology. Cognitive biases are often because of evolution. Some behaviors were good for primitive humans and animals that seem foolish today. The scientific method limits the results of cognitive bias.
Definitely Maybe
Definitely Maybe is the first album by Oasis. It was released under the label Creation Records on the August 30, 1994.
SN 1987A
[[File:New Hubble Observations of Supernova 1987A Trace Shock Wave (4954621859).jpg|thumb|250px|The remnant of SN 1987A]]
SN 1987A was a [[supernova]] in a [[Large Magellanic Cloud|small galaxy]] that is orbiting our Milky Way galaxy. The supernova was 168,000 light years away, and so happened 168,000 years ago. But it was 1987 when it was first seen. It was close enough that scientists found [[neutrino]]s before the light got to Earth.
SN 1987A is the only supernova that has been that close in modern times, It was the brightest object seen from Earth in over 400 years. There have been many others that were closer but they were before scientists had the tools to help them understand what was happening.
Kepler's Supernova
SN 1604 was a supernova seen in 1604. It was seen in the constellation Ophiuchus. SN 1604 is sometimes called Kepler's Nova or Kepler's Supernova or Kepler's Star since Johannes Kepler studied it. SN 1604 is the last supernova to have been seen in our galaxy.
Scott Stewart (director)
Scott Stewart (alias Scott Charles Stewart) is an American movie director, writer, movie producer and special effects maker.
Stewart worked at the special effects business called The Orphanage. Stewart directed and wrote the movie "Legion". "Legion" is an action movie and horror movie about the end of the world, also called the apocalypse. He directed the vampire and western horror movie "Priest". He has had actor Paul Bettany star in his first two movies.
Rhinoplasty
Rhinoplasty is an operation performed to change the shape, size or appearance of the human nose.
Chinstrap penguin
The chinstrap penguin ("Pygoscelis antarctica") is a penguin that gets its name from the narrow band of black feathers that goes under their "chin" from ear to ear. They are sometimes called the ‘stone-cracker penguin’ because of their squeaky and high pitched call. Chinstrap penguins are found in polar, shallow seas and coastal areas. Some penguins are born very pale and are called ‘Blonde’ penguins. There are more chinstrap penguins than any other penguins in the world.
They feed mainly on krill and fish. The chinstrap penguins make nests in round shapes made from small stones and take turns in sitting on the eggs, they can be left on the nest for 10 days.
These little penguins are only about tall and weigh about . Chinstraps may be small, but they are the boldest penguins of all.
Adélie penguin
The Adélie penguin ("Pygoscelis adeliae") is a Antarctic penguin that has a black head and back with a white chest and belly, and a white ring around each of their eyes. There are about 2.5 million Adélie penguins in the Southern Ocean around Antarctica. Adélie penguins travel the furthest to breed because they build their nests from stones and need to find stones. Adélies come ashore to breed in the summer. In the winter, they live on ice that floats off the Antarctic shore.
Adélie parents take turns keeping their chicks warm and fed. While one watches the nest, the other goes into the ocean to catch krill. The penguins carry the krill back to the nest in their stomachs. Then they regurgitate it to feed their chicks.
Most Adélie penguins incubate two eggs at a time. The little chicks hatch out at about the same time. One is usually stronger than the other and has a better chance of surviving.
When first born, the chicks are kept warm by their parents. But after two or three weeks, they grow a thick, woolly gray down. Then they join other chicks in creches, or nursery groups.
Adélie penguins are the smallest penguins in Antarctica. They weigh only about , or the weight of a typical house cat. They are about .
Katabatic wind
A katabatic wind is a very strong wind which blows downhill. They can be warm winds like the "föhn" wind on the north slopes of the Alps in Europe or the Chinook which blows down the Rockies in the US. They can also be very cold winds like those in Antarctica or Greenland. They are made when cold, dense air flows down from the ice cap to the coast. Sometimes these winds are called "fall winds". Along the Adriatic coast, the cold katabatic wind is called the "bora", and in France it is called the "mistral".
Galápagos penguin
The Galápagos penguins ("Spheniscus mendiculus") live on the Galápagos Islands. Because these islands are at the equator, the waters are warm not all penguins live in cold climates. They do not migrate.
Galapagos penguins have two bands of brown feathers on their faces and their beaks are thin and slender.
They weigh five pounds and are one and a half feet tall.
Macaroni penguin
The macaroni penguin is a crested penguins that gets their names from their crest. Macaroni penguins are known for their black faces and the orange-yellow crests that create a band across their foreheads.
Macaroni penguins live on islands on the edge of Antarctica, as well as on islands that lie south of Africa and the Americas. They make their nests on cliffs and hillsides.