Between one fourth and one third of all animal species in the world have become extinct in the last thirty years, according to data of the London Zoological Society cited by the BBC.
The population of land animals has gone down with 25%, of sea animals - with 28%, and of freshwater animals - with 29% in thirty years.
Human activity is currently wiping out 1% of all animals from the face of the earth each year. According to the Zoological Society's research, one of the greatest periods of animal extinction is currently going on the planet.
The research of the World Wildlife Fund over 1400 species of mammals, birds, fish, and reptiles has found that their population has declined with 28% in the last 35 years.
According to the WWF the threat for the extinction of animal species would continue in the coming thirty years as well mainly because of the expected climate change.