Deer and emperor penguins are among the species selected by the renowned environmental organization WWF to illustrate the threats facing thousands of animals around the world.
"Thousands of species are struggling with declining populations and a growing number of threats," WWF said in its annual summary, published on Thursday.
"The International Red List now lists more than 42,100 species of animals and plants as threatened," the organization said, referring to the International Union for Conservation of Nature's Red List of Threatened Species.
"In 2000, the world's largest population of wild reindeer in the Taimyr region in the Russian Arctic consisted of one million animals. Today, only a quarter of them remain,” according to WWF, citing climate change and poaching as the main reasons for the decline.
The organization also highlighted the plight of emperor penguins, saying nothing had been done this year to better protect the species.
"At current levels of greenhouse gas emissions, between 80 and 100% of all known emperor penguin colonies are at risk of extinction by 2100," WWF said.
"Meanwhile this summer's massive fish die-off in the Oder River, which runs between Germany and Poland, was also a setback for the reintroduction of the Baltic sturgeon, as thousands of young fish died," WWF said.
WWF also highlighted positive examples of species conservation, including the tiger population in Nepal, which was recovering well, as well as humpback whales in Australia.
The animals had been removed from the endangered species list due to a significant population increase.
"However, more measures are needed to protect whales from threats such as fishing, ship traffic and pollution," the organization said.