Mecistops leptorhynchus (Bennett, 1935) is among the least studied crocodylians worldwide, and little information exists on its movement patterns and habitat use.Using VHF radio tracking, we determined home range, core use areas and spatiotemporal interactions for 30 individual M. leptorhynchus (14 females and 16 males), as well as providing a preliminary assessment of their habitat preferences and emergence dynamics in the Echira and Ngové Rivers, Loango National Park (Gabon). During two periods in 2010 (March to June-106 days, and October to November-49 days) we recorded 447 relocations of all tagged individuals (mean of 15 relocations/crocodile). Individual home range varied from 3.03 to 164.83 ha (median = 17.91 ha) and core use area from 0.25 to 25.37 ha (median = 1.50 ha). Males exhibited the largest home ranges whereas females recorded the largest core areas. Subadults covered the largest areas at both spatial scale. These difference were not statistically significant.Interestingly, M. leptorhynchus showed more space sharing than other crocodylian species, though with significant temporal avoidance-likely an adaptive behaviour used to reduce risks of conflict in high density environments. Our emergence assessment, though potentially confounded by transmitter placement, indicated limited basking behaviour in this species with unknown effect on its detection probability. All individuals, irrespective of size and sex, principally used main water courses. Ultimately our findings provide the first data on M. leptorhynchus home range and social organisation, which may help direct targeted management strategies for this species. K E Y W O R D S emergence, habitat use, home range, protected area, spatial ecology, VHF telemetry Résumé Mecistops leptorhynchus (Bennett, 1935) est l'un des crocodyliens les moins étudiés au monde, dont très peu d'informations relatives à la structure des mouvements et l'utilisation de l'habitat existent. Nous avons utilisé un suivi radio VHF, pour déterminer le domaine vital et la zone d'utilisation centrale, la dynamique des interactions spatiotemporelles de 30 individus de Mecistops leptorhynchus (14 femelles et 16 mâles), et

West African crocodylians are among the most threatened and least studied crocodylian species globally. Assessing population status and establishing a basis for population monitoring is the highest priority action for this region. Monitoring of crocodiles is influenced by many factors that affect detectability, including environmental variables and individual‐ or population‐level wariness. We investigated how these factors affect detectability and counts of the critically endangered Mecistops cataphractus and the newly recognized Crocodylus suchus. We implemented 195 repetitive surveys at 38 sites across Côte d’Ivoire between 2014 and 2019. We used an occupancy‐based approach and a count‐based GLMM analysis to determine the effect of environmental and anthropogenic variables on detection and modeled crocodile wariness over repetitive surveys. Despite their rarity and level of threat, detection probability of both species was relatively high (0.75 for M. cataphractus and 0.81 for C. suchus), but a minimum of two surveys were required to infer absence of either species with 90% confidence. We found that detection of M. cataphractus was significantly negatively influenced by fishing net encounter rate, while high temperature for the previous 48 h of the day of the survey increased C. suchus detection. Precipitation and aquatic vegetation had significant negative and positive influence, respectively, on M. cataphractus counts and showed the opposite effect for C. suchus counts. We also found that fishing encounter rate had a significant negative effect on C. suchus counts. Interestingly, survey repetition did not generally affect wariness for either species, though there was some indication that at least M. cataphractus was more wary by the fourth replicate. These results are informative for designing future survey and monitoring protocols for these threatened crocodylians in West Africa and for other endangered crocodylians globally.