The noun tiger is used figuratively, especially in the phrases tiger for work and tiger for punishment, to characterise a person who has an insatiable appetite for something.
—Cf. the similar figurative use of the noun glutton, especially in the phrase glutton for punishment.

For example, the noun tiger is used figuratively in the following two passages from Dusty Answer (New York: Henry Holt and Company, 1927), by the English novelist and translator Rosamond Lehmann (1901-1990):

They made a wood fire and watched it sink to crumbling feathery ash round a glowing core; and they ate oranges and tomatoes and very young small lettuces stolen from the garden by Martin who was still, so Roddy said, a tiger for raw vegetables. But there were no onions: he declared he had given them up.
[…]
‘We’ll talk a little before we go. We must talk.’
He laughed—a normal teasing laugh.
‘A little conversation,’ he said. ‘ You’re a tiger for conversation, aren’t you?’

The earliest occurrences of the phrase tiger for work that I have found are as follows, in chronological order:

1-: From The Indian Mutiny and Australian Obligations, published in The Argus (Melbourne, Victoria, Australia) of Monday 19^th October 1857:

As it is possible, however, that the troops now in this and the neighboring colonies may be withdrawn for the purpose of assisting to quell the Indian insurrection, the present is a time at which some effort might be most appropriately and usefully made to increase the strength and efficiency of the Volunteer Corps already established in this colony, for the purposes of its own safety and defence. John Bull and his offspring are, indeed, such “tigers for work,” and such devout believers in the theory that anything to be really good must be regularly bought and paid for, in a business-like way, that a disposition not unfrequently displays itself to under-rate the Volunteer Corps and to speak slightingly of those who lay themselves at all open to the charge of “playing at soldiers.”

2-: From an article about a horserace that was to take place at Ballarat, Victoria, on Thursday 1^st October 1863, published in Bell’s Life in Victoria and Sporting Chronicle (Melbourne, Victoria, Australia) of Saturday 26^th September 1863:

The Archer of next Thursday is Mr. De Mestre’s horse in his very best form, and I cannot help thinking that he will make as great a show of those behind him as he did last year in the Melbourne Cup. His stable companion, Haidee, I doubt not is a mare of great excellence. I have never seen her, but those who have, and who are better judges than myself, pronounce her a stayer all over, with quarters that must send her along, with bellows that can never get out of order, and in the very zenith of condition—being, like Archer, a very tiger for work and a very glutton in her box.

3-: From Love in a Cottage, an unsigned story published in Cassell’s Magazine (London, England) of Saturday 11^th April 1868:

I have found, I think, the one woman in the world who can make me a truly happy man. I have known her for some years, studied her character, and the more I have seen of her, the more I have loved her. My income is not large, but with this one woman in all the world to help me, I think I could be a nobler and a better man. She has never known much comfort, poor thing, at home; and I should like to be able to make up with my warm love for what she has been robbed of for so many years. She is energetic and clever, prudent and far-seeing; I am young and active, and a tiger for work.

4-: From To the Early Train, published in The Leader: A Weekly Journal of News, Politics, Literature, Science, Agriculture, and Sporting (Melbourne, Victoria, Australia) of Saturday 24^th July 1869:

A great deal of pity is expended over the “houseless wanderer” who passes night after night without a roof to cover him. Of course, the H. W. is a paragon of perfection and the possessor of every virtue under the sun, together with a few not at present known to the ordinary inhabitants of this planet. He never gets drunk and then coils himself up in the first convenient spot in order to sleep off one debauch before beginning another; he is a very tiger for work, and never happy unless benefiting his species in some way or other—even if his benevolence should take the form of ridding the world of a nuisance by knocking his wife about the head with a brick bat.

5-: From The Three Brothers, by the Scottish novelist Margaret Oliphant (1828-1897), published in Saint Pauls: A Monthly Magazine (London, England) of October 1869:

“Mrs. Severn is no example for you. She was made for work, that woman. As long as she has her baby to carry about at nights, and her boys to make a row, and that child, Alice, with her curls,—why the woman is a tiger for work, I tell you.”

6-: From Training Notes. By a Tout, published in The Australasian (Melbourne, Victoria, Australia) of Saturday 5^th November 1870:

Sheet Anchor is not by any means the tiger for work he used to be; he is more sedate in his gait, and consequently may be expected to perform considerably better.

7-: From the transcript of a speech made by Sir H. Croft during the dinner held by the Ledbury Agricultural Society on Tuesday 26^th September 1871, published in The Worcester Herald, and Advertiser for Worcestershire and West Midlands Counties (Worcester, Worcestershire, England) of Saturday 30^th September 1871:

With regard to the work of last session, he was in hopes, that although the present Members of the House of Commons were real tigers for work, still, looking at the time which had been wasted, both sides of the House would go to the business of legislation next February with a repentant spirit, and that many questions of domestic interest would be grappled with, and brought to a successful issue.

The earliest occurrence of the phrase tiger for punishment that I have found is from In the Ring (By “The Amateur.”), published in The New Zealand Times (Wellington, New Zealand) of Saturday 30^th December 1911:

Dave Smith and Jack Lester are to meet at the Sydney Stadium on New Year’s night. The American has a big deposit lodged that he will tip the beam at 12st 7lb, but to do it he will need to have lived for a week on “a bottle of soda-water and a carraway seed.” However, if he can do it, and Tommy Burns is hardly the man to lose his money without knowing what he is up against, then the battle should be a stern one. Smith is undoubtedly the cleverer man, but Lester seems a tiger for punishment, and if the starvation diet has not weakened the latter too much he may wear Smith down. The latter is likely to start favourite.