The relevance of the Jaguar in Brazilian fauna is incompatible with the lack of literature regarding its reproductive behavior, showing that research in this area should be intensified. The knowledge of its basic reproductive behavior is extremely important for understanding the fertility factors of the species and the role it plays in its ecosystem. In this study, we analyzed 210 sequences of sexual behaviors of Jaguars Panthera onca starting from proceptivity of the female and ending with copulation; this sequence is called the copulatory behavior. Behavioral sequences were filmed, and the observed behaviors were analyzed and recorded including occurrence frequency. Different behaviors were observed in association with two types of copulation, it was understood that copulation occurs with and without penile penetration. The information found in the present study is valuable for the reproductive management of Jaguars.

Cryptorchidism is a genital alteration wherein one or both testicles fail to descend into the scrotum and has multifactorial causes. A free-range adult male was captured twice in the Pantanal of Nhecolândia to put a GPS collar and semen collection. Pharmacological semen collection, andrological examination and semen analysis were performed. At the first capture and during the andrological examination only the left testis was found, and the male qualified as cryptorchid. The penis had no penile spines at either procedure. The semen volume obtained at first and second capture was 435 and 160 μL, respectively, with a concentration of 618 and 100 x 106 sperm/mL, progressive motility of ~ 5% and ~ 1% and total morphological sperm abnormalities of 74% and 86%. The male was monitored by a GPS collar, but the signal was lost, making it difficult to re-captures and perform new seminal and ultrasound evaluations to discard monorchidism – exceedingly rare in felids. Genetic studies to assess the individual's homozygosity are necessary to verify whether cryptorchidism in this individual has a genetic factor.

The study of free‐living felids requires the capture of individuals from the wild to collect biological samples and to equip them with GPS‐satellite collars for telemetry monitoring. The traditional methods used by researchers to capture wild felids are box traps and trained hounds, both of which have disadvantages. We present the description of the foot snare and the adaptations required for the capture of jaguars and cougars, showing its efficiency. The foot snare consists of a combination of structures. It is composed of a thrower system, which is responsible for closing the steel cable noose on the paw of the animal; a holding system, which is responsible for securing the animal safely, after stepping into the trap; and a monitoring system, consisting of a VHF transmitter that allows remote monitoring of the snares. The snares are set on trails and roads according to the presence of tracks, scats and other evidence indicating use by the two species of large felids or as determined by monitoring camera traps. Thirty jaguars (16 females and 14 males) and six cougars (all males) were captured. Three jaguars in the Pantanal were captured more than once, therefore totalling 34 capture events. Snares have been demonstrated to be a safe and efficient method to capture these felids.