Giraffe numbers have plummeted in recent years, with conservationists warning of the "silent extinction" of the world’s tallest land animal. Just 97,500 now exist in sub-Saharan Africa, falling almost 40 percent since 1985, says the International Union for the Conservation of Nature. Check out this week's eco@africa show to see how giraffes are coming back from the brink of extinction in Niger.

These majestic creatures have suffered from disease, habitat loss and illegal hunting for bushmeat, as well as collisions with vehicles and power lines - there are now fewer giraffes than elephants in Africa. Campaigners say giraffes now face additional pressure from "trophy" hunters traveling to Africa to shoot their big-game quarry - these hunters mostly come from the US.

In 2016, researchers found that there are not just one but four distinct species of giraffe. The research, published in the journal Current Biology, is now being reviewed, but if formally recognised as four separate species, three of those four would suddenly be deemed more seriously threatened on the IUCN's list of endangered animals, hopefully prompting greater conservation efforts.

Giraffes' necks can be as long as six feet – despite only containing seven vertebrae, the same number as a human's, although a giraffe's are elongated. For blood to reach the brain, the heart must pump it to a height of two meters. Scientists are still trying to solve the mystery of how the giraffe got its neck.

Pregnancies are long, lasting up to 15 months, and end with the giraffe giving birth standing up – that means their offspring have rather a bumpy welcome into the world, having to endure falling more than five feet to the ground at birth. But baby giraffes are fast learners: they can stand within just 30 minutes of the birth and can run with their mothers only 10 hours after being born.

Giraffes eat most of the time, chewing through hundreds of pounds of leaves each week and must travel miles to find enough food. But its height can make drinking difficult and dangerous. To do so, they must spread their legs and bend down, making them vulnerable to predators. Thankfully, giraffes only need to drink once every several days, as they get most of their water from the plants they eat.

A giraffe's 21-inch tongue is crucial in helping them pluck leaves from branches–and also helps in the birth process. Giraffes graze on leaves and buds in treetops that few other animals can reach, with acacias a particular favorite.

Let's start with the good news. According to the latest Red List update, the number of mountain gorillas has significantly increased. The IUCN has said the number of animals has risen from about 680 a decade ago to more than 1,000 now. Intensive conservation action such as removal of snares has contributed to the rebound of the mountain gorilla, which inhabits the Congo region's jungles.

Fin whales are now considered vulnerable rather than the more worrisome label of endangered. Their number has roughly doubled since the 1970s, to around 100,000 individuals, according to the IUCN. The situation of gray whales has also been upgraded — from critically endangered to endangered. Bans on commercial whaling have made a real impact on conservation.

Yet the IUCN also issued warnings about the consequences of overfishing. For example, 13 percent of grouper species worldwide and 9 percent of the approximately 450 fish species in Lake Malawi in eastern Africa are threatened with extinction. "Depleting fish stocks are a serious concern for food security, particularly for coastal communities in developing countries," the IUCN said.

In a previous Red List update, the Mauritian flying fox — an important pollinator — moved from vulnerable to endangered. The bat population fell by a whopping 50 percent from 2015 to 2016 due largely to government-implemented culling sparked by alleged damage to fruit crops. The megabat species also faces threats from deforestation, illegal hunting and an increase in cyclone activity.

Invasive species are threatening a number of unique Australian reptiles. This grassland earless dragon has shifted from vulnerable to endangered. It often falls prey to feral cats, as well as changes to the intensity and frequency of bushfires. Like most native Australian wildlife, the reptile is adapted to environmental conditions that existed before European settlement.

Taking its name from "The Lord of the Rings" character Smeagol — aka Gollum — the precious stream toad is also on the list of species threatened with extinction. It is listed as vulnerable, largely as a result of expanding tourist resorts and complexes in its Genting Highlands habitat in Malaysia.

The population of keas, New Zealand's Bird of the Year 2017, is declining rapidly, mostly due to tourists who keep feeding the curious parrots junk food. As a result, the birds get used to trying novel food and end up eating poison bait meant to control pests such as rats, stoats, or possums, which destroy up to 60 percent of the birds' nests each year. You can see the connection, can't you?

Black-legged kittiwakes rely on certain key prey, like sand eels. But a lack of eels to eat means breeding colonies in the North Atlantic and Pacific are struggling to feed their chicks. Globally, the species is thought to have declined by around 40 percent since the 1970s. The main cause is overfishing and alterations in the ocean due to climate change.

The snowy owl is vulnerable, with recent population estimates much lower than previously thought. Climate change has hit the iconic Arctic bird hard, as it has increased snowmelt and reduced the availability of rodent prey. A quarter of bird species reassessed in the Red List, including the snowy owl, have become more endangered.

Five species of African antelopes — of which four were previously assessed as least concern — have been declining drastically as a result of poaching, habitat degradation and competition with domestic livestock. One of these is the gray rhebok, for which the Reebok sports brand is named.

The world's largest antelope, the giant eland — previously assessed as least concern — is also vulnerable. Its estimated global population is between 12,000 and 14,000 at most, with fewer than 10,000 mature animals. This species is declining due to poaching for bushmeat, human encroachment into protected areas and expansion of agriculture and livestock grazing.