Hi Gang, thought I’d drop in and insert my 2 cents worth. If you don’t mind, I’ll mention a few credentials so that while I might be wrong, at least you can see why I feel qualified to comment.
I’ve bred and shown Bengal cats for 6 years, as well as participating in feline rescues. I’ve worked as a veterinary assistant for 4 years, and completed half of a degree in veterinary technology. Bengals and Chausies (another breed I’ve been involved with) are derived from crosses between domestic cats and, respectively, Asian Leopard Cats (ALCs) and Jungle Cats (JCs). I have varying generations from the wild ancestor, so see a pretty wide range of behaviors. I average about 30 cats in residence, so I get to see LOTS of feces :). And I had the pleasure of babysitting a Serval for about 6 months while he recovered from orthopedic surgery.
I can’t answer the original question ‘do the big cats bury their feces’, but I can either find out for you or direct you to where you can find out (your choice). If you have a lot of curiousity about wild cats, you can go to http://www.lioc.org , go to the Links page, scroll down to the bottom,click on Felines-L News Group to subscribe to their e-mail list, and ask that question and any others you have. Many of the wild cat/large cat refuges/havens/captive breeding programs are represented on the list. Just don’t mention the name “Tippi Hedren” if you don’t want to get blasted! There are also lots of great info on the website and tons of links.
If you don’t want to go to that much trouble, I’m already a subscriber to felines-L and can drop your question into the discussion for you and bring back some answers in a few days.
You can also get lots of good wild cat info at http://lynx.uio.no/catfolk . But I don’t think you’ll find the answer to the feces question at either place because I took a quick look before posting here and didn’t see anything. It might be on one of the many websites linked from these two, or at one of the ethology sites, but the easiest thing to do is ask the experts on felines-L.
Following is some info from The Domestic Cat: The biology of its behavior, second edition; edited by Dennis C. Turner & Patrick Bateson, Cambridge University Press, copyright 2000, ISBN 0-521-63648-5:
Page 70:
"Faeces
Many species within the Carnivora use faeces, often with glandular secretions added, to convey information (Gorman & Trowbridge, 1989), but the evidence that domestic cats do this is only circumstantial. Near to the core of the home range, faeces are usually buried (Feldman 1994a), but they may be left exposed elsewhere (Macdonald et al., 1987). Cats usually sniff the places where they have just buried faeces, but tend not to do so after leaving them exposed (Macdonald et al.,1987). this suggests that one of the functions of burying faeces is to minimise the likelihood that the olfactory information they contain will be detected by another cat, although hygiene may provide a more parsimonious explanation. attempts to demonstrate that unburied faeces serve as territorial markers have produced equivocal results (Dards, 1979;Macdonald et al., 1987; Feldman, 1994a)."
Page 85:
"Faeces deposition
The method of faeces deposition varies according to species (reviewed in Wemmer & Scow, 1977). However, it is difficult to see if there is an evolutionary pattern to these differences or whether they are dependent on local conditions. Lindemann (1955, in Wemmer & Scow, 1977), found that the Canadian lynx (Lynx canadensis) and the European wildcat (F.s. silvestris) used two different methods, dependent on where the defaecation took place; faeces were localised and covered within territories, but left uncovered in prominent positions at points between territories (which were used as mating rendezvous sites in the lynx). This finding suggests that the method of defaecation may depend on local conditions rather than on phylogeny."
Now, for some personal observations:
The Serval never covered his feces while living here - defecated neatly in the (large!) litter box, but never covered.
I agree with dragonlady that a dominance issue is involved at least part of the time. For example, none of my adult males cover their feces, but kittens and junior females usually do. Dominant females often leave their feces uncovered. In a multiple-cat situation (where I have more than one adult housed together) uncovered feces are usually immediately investigated by the other cats; if the group consists of a whole male and one or more females, the male will immediately investigate uncovered female feces, but the females rarely show much interest in the male’s uncovered deposits.
I also have a female F1 Jungle Cat/domestic cat hybrid who defecates in her litterbox EXCEPT when she is in heat. When she was housed indoors, she would defecate in front of the doorway to her pen - this was usually my first indication that her heat cycle was beginning. When moved to an outside enclosure, she began defecating on the strip of concrete between the rear of her house and the back of her enclosure, which is exposed to an overgrown “jungly” area.
From these observations, I concluded (possibly incorrectly) that females also use uncovered feces to advertise their readiness for mating. Since they also engage in urinary spraying behavior, I’m guessing that fecal depositions have additional advantages - perhaps the scent is stronger, or the solid material preserves the scent for a longer period of time, or the scent lasts longer because it is not easily washed away by rain, etc., or maybe the little pile is more noticeable.
However, since most of my cats have at least a small percentage of wild (ALC)genes and the ALC has some peculiar elimination habits that appear to be ‘hard-wired’ (since they appear in cats 7 or 8 generations removed from any wild ancestor), I can’t say that these behaviors also appear in a regular basis in the general population of ordinary domestic cats.
I don’t know much about the elimination patterns of JCs, but am somewhat familiar with those of the ALC because of the above-mentioned ‘hard-wiring’ - many Bengal breeders deal with this on a daily basis! However, hormones are also involved in some way as these elimination problems are not frequently seen in altered cats - only whole males and females, and sometimes retired breeders who were altered after being sexually active for several years (so that the elimination patterns have probably become habitual).
Anyway, to move on here … ALCs in captivity do not use litterboxes. I’ve been told that, in the wild, they commonly both urinate and defecate into running water - in captivity, apparently their water dish will suffice :rolleyes:. This is one of the ‘hard-wired’ traits I’ve referred to - I have several adult Bengal males, fourth or later generation, for whom I have to hang a drip waterer to keep them supplied with fresh water. They promptly urinate into any dish of water placed in their quarters. One male will leave the dish alone as long as their is any water in it, but will urinate in it if he runs out of water and the dish is empty! A couple of males I have owned went through a several-month-long period after reaching sexual maturity when they urinated in their drinking water, then suddenly stopped and never did it again. 
I had never had a problem with any cat defecating in a water dish until recently; however, I now have a young female who has started doing this upon reaching puberty. sigh And not only is she 8 generations from a wild ancestor, she is only 2 generations from a totally-domestic outcross, so should have fewer ALC genes than the average Bengal!
I’ve also never had a problem with cats defecating on their food, but I do have one male who will urinate on his leftover food as long as it is on the floor. He will usually not do this as long as his food is placed on a shelf - I wasted a lot of very expensive food before I figured this out.
So, FWIW, there is my complete and total knowledge of wild cat poop. More than you really wanted to know, I’m sure!