Shuker received a BSc in pure zoology from the University of Leeds and a PhD in zoology and comparative physiology from the University of Birmingham.He is a Scientific Fellow of the Zoological Society of London, a Fellow of the Royal Entomological Society, a consultant for the Centre for Fortean Zoology, and a member of the Society of Authors.

Shuker is one of the leading cryptozoologists in the English speaking world. He has authored numerous articles and sixteen books, including the cryptozoological works Mystery Cats of the World (1989), The Lost Ark: New and Rediscovered Animals of the 20th Century (1993; expanded in 2002 as The New Zoo), and In Search of Prehistoric Survivors (1995), as well as two worldwide bestsellers - Dragons: A Natural History (1995; reissued in 2006), and The Unexplained (1996; reissued in 2002). He is also a published poet - his first volume of poetry, Star Steeds and Other Dreams, appeared in 2009.

Shuker was the first cryptozoologist to bring to widespread public attention a considerable number of cryptids that were previously little-known. These include the Sri Lankan horned jackal and devil bird, Gambo the Gambian sea serpent, Goodenough Island mystery bird, New Guinea ropen and devil pig or gazeka, Scottish earth hound, Indonesian veo and horned cat, New Caledonian du, Irish dobhar-chú, Shatt al Arab venomous mystery fish, Zanzibar makalala, Ethiopian death bird, Zululand kondlo, Arctic North American waheela, Kellas cat, Mongolian Death Worm, Hungarian reedwolf, Fujian blue or Maltese tiger as shown on the cover of Mysteries of Planet Earth (1999), Welsh cenaprugwirion, bigfin squid, St Helena sirenian, Timor Sea ground shark, and crowing crested cobra.

Aside from his own publications, Shuker pens two regular cryptozoological columns ('Alien Zoo' and 'The Lost Ark') in Fortean Times, is a contributing editor and cryptozoological columnist for Strange Magazine, and is a regular contributor to Fate, Paranormal and related publications. In addition, he is the zoological consultant for the Guinness World Records.

He has acted as a consultant for several television specials and series, including Discovery TV's Into the Unknown. He has also served as a question setter for the BBC's quiz show Mastermind.

In November 2001, Shuker became a £250,000 prize winner on the British version of Who Wants to Be a Millionaire?.

In 2005, Shuker was honoured by the naming of a new species of Loricifera after him, Pliciloricus shukeri.