Crocodiles

• American crocodiles are listed as endangered, except for in Florida where they are listed as threatened, as of 2011.Jupiterimages/Photos.com/Getty Images
  
  Due to the trade of crocodile skins in the 1950s, crocodiles became endangered. Subspecies of the crocodile that also entered the endangered species list include the spectacled caiman, Caiman yacare and the Apaporis River caiman. A total of 85 percent of the population decrease is due to the skins entering the product market. Due to the drastic decline in population, it became illegal to trade and kill crocodiles.
  
  

Nene

• Hawaii Volcanoes National Park has a carefully monitored recovery program for the Nene, Hawaii's state bird.Thinkstock/Comstock/Getty Images
  
  The Nene bird, or Hawaiian Goose, is the state bird of Hawaii. Captain Hook brought them to Hawaii in 1778. In the 1950s the Nene population was reduced to just 30 birds. This was mostly due to the introduction of predators, which included dogs and mongooses. Also, the birds were forced to higher ground when the lower ground was destroyed. Higher ground meant colder temperatures, which made it harder for the young chicks to survive.
  
  

Tigers

• Tiger bones have been used to treat many illnesses, including ulcers, burns, malaria and dysentery.Medioimages/Photodisc/Photodisc/Getty Images
  
  The tiger population started to decline and were near extinction in the1950s. In China there was a 40 percent decrease starting in the 1950s, and the population went down to a mere 30 or 40 tigers. They became endangered due illegal poaching and to the growing human population. Also, tigers were being aggressively poached for use in making traditional Chinese medicines.
  
  

Red Panda

• The red panda is about 40 inches long from its nose to the tip of its tail and has a face similar to a racoon's.Tom Brakefield/Stockbyte/Getty Images
  
  The red panda of China experienced a 40 percent decline in the 1950s, which placed it onto the endangered species list. Sadly, the red panda's population decreased due to being attacked by domestic dogs. Another reason for the decrease in population was due to being caught in traps put out for other animals. In 1975 the Convention on the International Trade in Endangered Species banned the trading of red pandas worldwide. This was done in an attempt to keep the red panda population from further decline and to keep them from becoming extinct.