Paintings of dogs and cats are highly collectable, generally much loved and they frequently fetch high prices at auction.
Mr Alistair Laird, an expert in 19th century paintings at Bonhams in London, says the most valuable paintings date from the last century. The best are oils on canvas - rather than watercolours or prints. Certain artists, like Sir Edwin Landseer, John Emms and Arthur Wardle, specialised in the genre and their work commands high prices. "If you've got an original oil painting by Landseer, it would be worth a fortune. Works by Landseer have fetched up to £400,000 or £500,000," he says.
The breed of the dog can also affect the value of a work. The most popular breed is the King Charles spaniel, "cute-looking" dogs which tend to be "owned by wealthy people and they subsequently come and buy the paintings as well," Mr Laird says.
Pictures of rare breeds like the Irish water spaniel also do well. "People who own them seem to go mad for them," he says. Bonhams sold a picture of this breed some years ago. "It wasn't a great quality painting. It wasn't signed at all. We had it in for £400 to £600 but because it was a water spaniel we got £4,000 to £5,000 for it," he says.
So an unsigned picture by an unknown artist could be valuable "if the actual dog is of something really rare like the Irish water spaniel or if it's something really popular like the King Charles spaniel", he says.
Other factors to be considered in valuing art in the genre is whether it's a good or indifferent example of the artist's work, its composition and condition "and those sorts of things, I'm afraid, are very difficult for a layman to tell, to be honest", Mr Laird says.
Lovers of cat pictures constitute a very different collecting market. "People who like dog pictures, don't like cat pictures, and vice versa. It's a very specific collecting area," he says.
Certain artists specialise in cat paintings, like Horatio Henry Couldery. "He specialised in doing pictures of cats chasing rats down holes and very cute pictures of kittens."
His work has "amazing detail - really photographic quality". A couple of his paintings in a Bonhams auction taking place in New York on February 9th next are expected to fetch "around the £10,000 mark", he says.
According to Ms Rowena Neville of the Irish Museum of Modern Art in Kilmainham, Dublin, dogs and cats also feature in the work of several Irish artists. For instance, John Kindness uses dogs a lot in his work, while Pauline Bewick - whose work is collected by many - has used cats in some of hers. Meanwhile, prices fetched at a recent Christie's sale include: £3,680 for Flushing out a Pheasant by Pierre Jules Mene (estimated £1,500 to £2,000); £9,200 for Three Greyhounds by Arthur Wardle; and a Wardle study of a Scottish terrier which fetched £8,970.
A painting of a bulldog by Frederick Thomas Daws (estimate: £400 to £600) sold for £2,070; a Pekingese by Henry Crowther fetched £2,875; An Irish Red and White Setter flushing out a Mallard by Arthur Heyer (estimate: £600 to £800) went for £1,725.
Kittens by Josef Heimerl (estimate: £600 to £800) sold for £1,380, despite being small - only 8 1/4 inch by 10 1/4 inch. Half Asleep by Gabrielle Rainer Istvanffy went for £1,150 (estimate: £700 to £900), while Jules Leroy's A Chacun Son Tour, with one kitten lapping at milk while another goes through her mother's legs to get to it, sold for £2,760.
