There are many animals that have gone from being fully healthy and readily available in large quantities to dwindling and eventually extinct. Although a large number of these animals existed well before humans were around, a large part of the more recently extinct animals happen to have gone extinct due to human intervention.
The dodo bird is one of the well known extinct species. It existed on a small island and was available there for quite some time. When humans came into the picture they started to catch these flightless birds and eat them. They were all captured and eaten and eventually the species disappeared. Along with the dodo bird went a species of plant that relied on the bird to crack its very thick nuts to be distributed for growth.
Another species that has gone extinct recently is the thylacine or Tasmanian tiger. The thylacine was a species of marsupial (pouched mammal) that looked very much like a dog with a beautiful striped coat just like a tiger. Although the thylacine was a very avid hunter and was very good at surviving, human intervention forced them to extinction. The last one was in an Australian zoo until it passed away from natural causes.
As human continue to push into locations such as the densely populated rain forests, they are taking the homes and areas of many species of animals. They are being driven to extinction further each day and the endangered animals lists are getting larger each day. It is important for everyone to educate themselves about what they can do to prevent more animal species from going extinct. Each species on earth is here for a reason while each animal has its own job to keep the earth balanced.