- You may be looking for Kate Lethbridge-Stewart, who bore the nickname "Tiger" as a child.
In 120 AD, the Tenth Doctor found himself opposing lions, tigers and bears in a Roman amphitheatre. At one point, a tiger ran towards him, but he neatly jumped over it, and the tiger went on to maul its trainers, who had badly mistreated it. (PROSE: The Stone Rose)
A tiger was one of the animals on board the Ark in circa 10,000,000. The First Doctor, Steven Taylor and Dodo Chaplet encountered it, and were surprised to find that it was not aggressive. (PROSE: The Ark)
Amongst the known breeds of tiger on Earth were sabre-toothed tigers (which became extinct in circa 9000 BC), Siberian tigers, Malayan tigers, and Bengal tigers. (PROSE: The Eight Doctors, PROSE: The Last Dodo, PROSE: Pack Animals)
There were at least two species of shapeshifting tiger-like species: an unnamed species (PROSE: Old Flames) and the Tygers (PROSE: The Eye of the Tyger). Gideon changed into a Tiger-like Humanoid. (COMIC: Universal Monsters)