The tiger cats (Leopardus tigrinus/Leopardus guttulus) are part of the ocelot lineage, one of the youngest of all cat lineages. They pose an exquisite genetic puzzle. They were recently acknowledged as two distinct species, given their genetic differentiation. However, it is likely that the current Central American subspecies, called Leopardus tigrinus oncilla, comprises a different species too. The Costa Rican population and the one of Central and Southern Brazil (now called Leopardus guttulus) have been isolated for approximately 3.7 million years. These two populations show a high level of divergence comparable to the one between species of the Leopardus genus and both populations have a low genetic diversity. To add more genetic oddity for the tiger cat species, there has been ancient historic hybridization between the pampas cat (L. colocola) and L. tigrinus, intense hybridisation with margays (L. wiedii) and ocelots (L. pardalis) in Venezuela, Colombia, Ecuador, Bolivia and Argentina, and ongoing bi-directional hybridization between L. guttulus with the Geoffroy's cat (L. geoffroyi). However, there has been no indication of mixing whatsoever between the two former single species. In other words, tiger cats mixed with other species but not between themselves! The Southern tiger cat is recognised as a monotypic species.

The tiger cats are small cats with a slender body, proportioned like a house cat (Brazilian, i.e. slender built, not bulky like European or American house cats). However, whereas some individuals look small, weighing only 1.8 kg, others are large with a weight of ca. 3.5 kg. Both species present the same body measurements. Males are slightly, but significantly, larger than females. At first glance, the tiger cat species seem to be cryptic. However, they do show some subtle differentiation on ground color, spot pattern, and morphology, which are not easy to tell apart and shows some slight regional variation within the northern species, too. Northern tiger cats (L. tigrinus) from the western part of their range show a darker ground colour varying from dark or orangish brown to yellowish and greyish brown. Their rosettes are medium-sized and tend to form small- to medium-sized oblique bands arranged in scapular inguinal direction. Meanwhile, the northern tiger cats from eastern South America have a lighter ground colour with a spectrum from light yellowish brown to pale yellow and greyish yellow. Their rosettes are smaller, with usually narrow and discontinuous rims and do not coalesce into oblique bands. The ground colour of southern tiger cats ranges from dark yellowish brown to ochraceous buff. Their rosettes have thicker, continuous rims, rarely coalescing into smaller oblique bands. Melanism is common in both species. On the one hand, the northern tiger cat has a lighter built, seeming often to have slender body, legs and tail. The southern tiger cat, on the other hand, tends to look slightly stockier, with a thicker tail and smaller rounder ears. Nevertheless, individuals of both species can diverge from their norm and some do look very cryptic. The paler belly fur is covered with dark spots. The large ears of both species have a black backside with a central white spot. The southern tiger cat’s tail has seven to thirteen irregular thin rings, and a black tip. The northern tiger cat has a less conspicuous, thinly ringed tail. In both species the tail measures about 60% of the head and body length. Both tiger cats look very similar to the margay (L. wiedii), making it difficult to distinguish the three. The tiger cats’ fur is not as thick however, its patterns tend to be less dark and blotchy, with abundant solid dot-like spots and open rosettes, which tend to be smaller and more numerous. Moreover, its body is more slender, its paws proportional to its size, and its tail shorter than that of the margay. In all tiger cats the nape hair slants backwards, differently from both ocelot and margay, but similar to Geoffroy’s cat. The southern tiger cat looks similar to Geoffroy’s cat, with whom it hybridizes. It differs by being smaller, without a bulky head and without the typical paired dots that usually do not form rosettes in the latter.

The southern tiger cat is classified as Vulnerable in the IUCN Red List, as well as in the National Red List of Brazil. In the state of Bahia, Brazil, it is listed as Endangered. Population decline by almost 50% in 8 years was observed in Santa Catarina state, Brazil, one of the most important areas for the conservation of the species. This reduction may have been caused by prey reduction. The southern tiger cat also declined in other areas by more than 50%. Its global population was estimated at 6,047 mature individuals.

Southern tiger cat population densities vary, but tend to be low throughout most of its range, especially in regard to what would be expected of such a small cat species. Given its body size, expected density would be 91 individuals per 100 km². Meanwhile, southern tiger cat occurs at densities typically of 1–5 per 100 km². Especially in protected areas it is very rare, most probably due to the negative impact of the ocelot. Only in a few areas, where ocelots are absent or rare, it reaches densities of 15–25 per 100 km².

The southern tiger cat ranges from Central to southern Brazil, eastern Paraguay and north-eastern Argentina. The species is absent from the Paraguayan Chaco. The population in Bolivia would probably be assigned to L. tigrinus. The northern limits of its geographic range are still unclear. It reaches Central Brazil in the states of Minas Gerais, Goiás and the Atlantic forest of central-south Bahia in the northeast region. Whether it overlaps with Leopardus tigrinus and to what extent is still not known. 

The southern tiger cat inhabits a variety of habitats, from dense tropical and subtropical rainforests, deciduous/semi-deciduous, and mixed pine forests, to the open savannah, and beach vegetation, both pristine and disturbed. A habitat model for Misiones, Argentina, showed southern tiger cats to be mostly associated with native Atlantic forest. In the Pantanal (wet/swampy savannah), it is very rare and has been recorded only in the dry savannas, not in the marshy areas. The southern tiger cat can also inhabit disturbed formations, and was also found in abandoned Eucalyptus plantations. Its occurrence near agricultural fields is nevertheless limited by the presence of natural cover. Thus, in mosaics of forest or savannah, and small-scale agriculture, both telemetry information and scat analysis, indicate that it uses the natural formations and does not venture deep into the agricultural areas per se, but only uses their borders. Moreover, in such areas rodent abundance can be elevated. Known altitudinal range of the southern tiger cat is below 2,000 m.

Since the southern tiger cat was separated from Leopardus tigrinus, its inclusion on CITES Appendix I is necessary to be made. It is protected over part of its range. Hunting is prohibited in Argentina, Brazil, and Paraguay.

As the southern tiger cat does not occur in high numbers anywhere and ocelots are the dominant and most abundant felid in most protected areas, southern tiger cat is probably most frequent outside protected areas, where habitats are undergoing high rates of destruction and/or are highly fragmented. Thus, conservation efforts should be focused on the areas outside protected areas. The state of Santa Catarina in Brazil has been considered to harbour the best and likely most viable population of the southern tiger cat, given the extent of its remaining Atlantic forest and the cat’s presence in decent numbers in local Conservation Units, mostly due to the absence of ocelots. Nevertheless, no conservation units within the southern tiger cat’s range in Brazil are expected to house even 500 individuals, with most expected to sustain far less than 200.

Further research on the ecology, natural history and threats is urgently needed for both species of tiger cats. To monitor and understand the extent of hybridization with Geoffroy’s cat is another research priority.