The jaguarundi (Herpailurus yagouaroundi) is phylogenetically part of the puma lineage, thus being closer related to the puma (Puma concolor) and the cheetah (Acinonyx jubatus) than to the other Neotropical cats. The jaguarundi is regarded as a monotypic species. Like the cheetah, the jaguarundi cannot retract the claws of its hind paws completely, and its behaviour resembles the puma more than other medium-sized cats in the same habitat.

The jaguarundi has a small, thin and elongated head, small close-set eyes, wide-set very rounded ears, a low-slung slender body, short legs and a very long tail, which gives it a unique appearance; it is sometimes in fact called "otter cat". The coat of the jaguarundi is short and uniform with three colour phases, brownish-black, grey, and yellowish-red. The head and the belly often times present a lighter colouration than the body. The reddish phase tends to be seen more often on open/dryer habitats. In fact, in the semi-arid Brazilian Caatinga scrub it is the most frequent colour morph. The blackish phase, on the other hand, seems to be more associated with rainforests. Nevertheless, all colour phases could be found in all environments. Sometimes there are markings on the face, belly or limbs. These markings can either be natural discolouration of the fur, but more commonly they are scars. Since unique markings are however generally uncommon, it is very difficult to identify individuals and make population size estimates from camera trap records or sightings.  

The jaguarundi is the most widely distributed small felid in the western hemisphere, and the second most widespread carnivore in the Americas after the puma, however concrete information about its population density is sparse. The jaguarundi is listed as Least Concern in the IUCN Red List as well as in the National Red List in Argentina and Nicaragua. It is classified as Threatened in Mexico, and Vulnerable in Brazil. In Guatemala the jaguarundi features on the List of Threatened Species (IeA) due to its small population size.

The jaguarundi was considered to be relatively common over much of its range for many years, perhaps because it is diurnal and uses open habitats. However, research indicates that it may be uncommon and a low-density species often found at densities of 1–5 individuals per 100 km² or even lower. A recent study in southern Brazil determined the minimal density of jaguarundi in a combined area of 80.57 km² to be a mere 4 individuals per 100 km². Other studies however suggest that the lack of records may not necessarily reflect abundance, but rather their elusive habits.

The jaguarundi’s distribution range extends from Mexico through to Colombia, Ecuador and Peru, to central Argentina, Paraguay, Brazil and Uruguay. There may also be a few individuals in the southern USA, however updated reports are lacking, and competition with the bobcat is likely to limit their distribution there. The jaguarundi generally occurs up to 2,000 m elevation and is considered to be more a lowland species. However, in Colombia it was reported up to 3,200 m. A recent study also published the first record of jaguarundi on the western slopes of the Peruvian Andes, an area in need of further monitoring of the species to determine the extent of its distribution and habitat requirements.

The jaguarundi has a remarkable characteristic which is very unusual in cats: it uses at least thirteen different calls to communicate. These range from purring, whistling and chattering, up to chirping like a bird.

In contrast to many other felids, the jaguarundi is strictly diurnal and hunts generally on the ground. Compiling camera trap records from various studies, it appears that they are most active between 08:00 h and 12:00 h and again between 16:00 h and 20:00 h. In a radio telemetry study in Belize, activity peaks were from 14:00 h to 16:00 h with very little activity after sunset. This pattern was also confirmed through camera trap studies in Brazil and Argentina. This behaviour enables the jaguarundi to segregate and thus minimize competition with the nocturnally active ocelot (Leopardus pardalis), the predominantly crepuscular and nocturnal puma (Puma concolor), and especially with the margay (Leopardus wiedii). The potential for competition between the ocelot and the smaller felids leads to the dominant ocelot negatively impacting the other species through the threat of interspecific killing/intra-guild predation or interspecific resource competition. However, due to its diurnal activity, prey availability has a greater influence on the spatiotemporal ecology of the jaguarundi than the pressure of dominant competitors such as the ocelot, puma and jaguar, despite overlapping home ranges.

It is however important to note that in a study between 2014 and 2016 in Carlos Botelho State Park, a large protected area (370 km²) in São Paulo State, Brazil, analysis of puma scat indicated remnants of jaguarundi. Because the feeding habits of the jaguarundi and puma are very different in such large protected areas, this interspecific predation event was in fact one of intraguild predation for feeding purposes, as opposed to resource competition.

In spite of its mostly terrestrial activity the jaguarundi is a skilled and agile climber and swimmer. They can jump up to 2 meters in the air to catch birds, and have been seen pursuing marmosets up in trees. Its arboreal capabilities should be no wonder, given its very large tail. Although the jaguarundi is considered a solitary carnivore, it has been observed travelling or foraging in pairs. Nevertheless, these could have simply been mother and pre-dispersal progeny.

Jaguarundis may travel up to 7 km per day. Few studies of home range size have been undertaken and thus ranging behaviour is not well understood. In the savannas of Brazil, home ranges for males and females varied from 18 to 40.2 km², whereas in a forest and forest/agriculture mosaic in Brazil it ranged from 1.4 to 34.9 km². In a low tropical forest/agriculture mosaic in Mexico, the mean home range of eight males was 9.6 km², whereas those of five females were 8.9 km². In Belizean rainforests however, home ranges for male jaguarundis were very large, several times larger than those reported for sympatric jaguars. One female used a home range of around 20 km², while two males used home ranges of 88 and 100 km². The home ranges of the two males overlapped less than 25%. In this way, although jaguarundi home range is larger than expected for its body size, it is still within the same pattern as those of other sympatric Neotropical felids.

Because jaguarundis have a polyestrous breeding cycle, meaning they are able to go into heat several times per year, they do not have one defined breeding season. The duration of the estrous cycle typically ranges from 51–56 days, where estrus lasts for 2.4–3.9 days. The jaguarundi’s gestation period ranges between 72–75 days, producing litter sizes of 1–4 offspring.

Cubs open their eyes at about six to eight days, leave the den at four weeks and start with solid food at four to five weeks but still suckle up to 60 days. The age at sexual maturity for females has been reported to vary from 17–26 months.

Jaguarundi populations of North and Central America are included in the CITES Appendix I since 1987, and all others are included in Appendix II.

The jaguarundi is protected over much of its range and hunting is prohibited in Argentina, Belize, Bolivia, Colombia, Costa Rica, French Guiana, Guatemala, Honduras, Mexico, Panama, Paraguay, Suriname, Uruguay, U.S. and Venezuela. In Peru hunting is regulated and the jaguarundi is not legally protected in Brazil, Ecuador, El Salvador, Guyana and Nicaragua.

A study in Colombia suggested there to be no spatial segregation between competing species such as jaguarundi, ocelot, puma and jaguar (only temporal), and that wild felids significantly avoided pasture areas and palm oil plantations. They indicated the importance of implementing conservation strategies that benefit the entire guild simultaneously, by using already modified areas such as pastures for the expansion of agricultural land.

The ongoing fragmentation of southern and central America’s natural land, poses a risk to the jaguarundi’s survival. Effective conservation of smaller felid species such as the jaguarundi depends also on strategies implemented outside protected areas. Moreover, effective conservation strategies for the jaguarundi require the immediate development of long-term monitoring programmes. Camera trapping appears to be the only effective method of jaguarundi detection to date. However, considering the low detection rate, this either indicates that populations are lower than thought, or more effective monitoring methods must be investigated. Some studies have used camera trapping coupled with another method such as track or scat identification, which although labour intensive, appeared successful in expanding the known distribution of this rarely detected species.

As little is known about the jaguarundi, its status should be periodically reviewed and there is an urgent need for further research on its ecology, demographics and natural history in order to identify threats and their impacts as well as to ensure that adequate conservation measures can be implemented.