Things we lost... Honshu wolf.

The Honshu wolf (or Japanese wolf) was the smallest wolf existing in the world, as it was only 84 cm long (not counting the tail) and 39 cm tall. 

In the Japanese Islands it was called "the howling God" and it was respected but also widely feared, so much so that in the country houses people hung talismans outside to protect themselves from those beasts. 

At the end of the 19th century, Japan knew an unprecedented process of industrialization and this led to the felling of many forests where the small wolf lived. 

Furthermore, an always more ruthless hunt to this animal began, with a bounty of 10 YEN by the government for each specimen. 

Tremendous rabies outbreaks finally decimated them. 

The last specimen was killed in 1905 (same fate befell its "cousin", the Hokkaido wolf). 

(Thanks to Lorenzo S. for helping me writing this post)

Things we lost... Caribbean monk seal.

The Caribbean monk seal was a peaceful seal, very similar to its Mediterranean "cousin". It lived in big colonies among Cuba, the Netherlands Antilles and Jamaica. 
In 1494, Christopher Columbus saw them for the first time and he immediately ordered to kill eight of them to feed the ship's crew. 
Since then, the population of Caribbean seals had a meltdown; for centuries, the crews of European ships en route between Europe and the New World have been hunting them for their meat and their fur. 
It definitively became extinct during the 50s of 1900. 

(Thanks to Lorenzo S. for helping me writing this post)

Things we lost...The Atitlán grebe.

The giant grebe was a podicipedidae native of Guatemala (Podilymbus gigas) which was discovered in 1929. 
It became extinct because of the introduction in the homonyous lake of the smallmouth bass (native of North America) for sport fishing. This fish killed the nestlings and large quantities of grabs and fish which were the main food source of the grebe. 
In 1983 there were only 32 specimens left and in 1989 the last two were sighted. After their disappearance this species was officially declared extinct. 

(Thanks to Lorenzo S. for helping me writing this post)

Things we lost...Carpathian and Caucasian wisent.

BISON BONASUS HUNGARORUM 

The Carpathian wisent was a subspecies of the European wisent which lived in the Carpathian Mountains, in Moldova and in Transylvania. 
Too close to central Europe, he was hunted until the extinction. 
The last specimen was shot down in 1790 in Transylvania. 

BISON BONASUS CAUCASICUS 

The Caucasian wisent was a subspecies of the European wisent which was once widespread in the Caucasus Mountains. 
It was prey to the Caucasian tiger (extinct) and to the Asian lion (which today is extinct in that zone), as well as to bears and wolves. 
In the 17th century he still populated wide areas of the western Caucasus. At the end of the 19th century human settlements became more numerous and the wisent population was reduced to approximately 1/10. In the 60s of the 19th century the wisent population was of about 2000 specimens, which were reduced to 500 in 1917 and to 50 in 1921. 
In 1927 the last 3 specimens were shot down. 

(Thanks to Lorenzo S. for helping me writing this post)