HABITAT AND ECOLOGY The Spectacled Caiman is a medium-sized crocodilian (maximum total length in males 2.7 m; Ayarzagüena 1984), that is extremely adaptable in terms of habitat requirements, occupying rivers, creeks (caños), lagoons, lakes, borrow pits, swamps, wetlands, dams, and marshes (Medem 1981). Female Spectacled Caimans reach sexual maturity at about 1.2 m total length and lay an average of 28-32 eggs in a mound nest, usually during the annual wet season (Thorbjarnarson 1994; Velasco et al. 1996). A close relationship between precipitation in certain months and the proportion of females that reproduce in that year has been reported (Ayarzagüena and Castroviejo 2008). Ayarzagüena and Castroviejo (2008) summarize the species’ ecology and behavior in detail. They comment that the genus Caiman, along with Alligator, shows the most elaborate behaviors known in crocodilians. Spectacled caiman behavior includes complex sound signals: “warning calls” emitted by female to the young; “distress call” emitted by juveniles; and, “group cohesion calls” emitted by all individuals. Males display social behaviours: “vertical tail” and “arch tail” with sub-audible vibrations, barks, and visual displays. Another important characteristic described by these authors is that hatchling and juvenile groups remain together under female care for 12-18 months. Initial studies on Spectacled caiman ecology were conducted in both the Venezuelan llanos and Colombian Caribbean (e.g., Chirivi 1973; Staton and Dixon 1975; Medem 1981; Seijas 1984, 1986). Subsequent studies report on life history traits such as feeding habits (Thorbjarnarson 1993, Allsteadt and Vaughan 1994, Da Silveira and Magnusson 1999, Bontemps et al. 2016), nesting ecology (Chirivi 1971, Staton and Dixon 1977, Thorbjarnarson 1994, Escobedo-Galván 2006, González-Desales et al. 2016), morphology (Busack and Pandya 2001, Macip-Ríos et al. 2012, Okamoto et al. 2015), parasites (Magnusson 1985, Charruau et al. 2016), injuries (Magnusson 1985, Seijas et al. 2003), growth (Magnusson and Sanaiotii 1995, Pérez 2001), and some demographic parameters (e.g., Allsteadt and Vaughan 1992a; Bolaños et al. 1997; Cerrato 1991; Flores 2005; Escobedo-Galván and González-Maya 2006, 2008; Martinez-Ibarra et al. 1997; Ouboter and Nanhoe 1987, 1988; Pacheco 1990; Ron et al. 1998; Perez 2001; Balaguera-Reina et al. 2010; Balaguera-Reina 2012; Moreno-Arias et al. 2013; Barão-Nóbrega et al. 2018). The Spectacled Caiman appears to have been resilient to commercial hunting for several reasons, particularly the small size and young age at which reproduction commences and hunting focus on large adult males. Additionally, Spectacled Caimans lay eggs on almost any type of substrate, and this lack of selectivity is advantageous over other more selective sympatric species (e.g., C. acutus, C. intermedius). The near extirpation of larger, sympatric crocodilian species of greater commercial value, may have assisted Spectacled caimans. In Brazilian Amazonia, they occupy habitats formerly dominated by Melanosuchus niger (Magnusson 1982). In the llanos of Venezuela and Colombia, the proliferation of man-made water bodies (e.g., borrow pits) has increased the carrying capacity for caiman populations. The ecological adaptability of the Spectacled caiman is evidenced through its rapid population growth where it has been introduced, both accidentally and deliberately. Introduced (feral) populations are established in the United States (especially Florida), Puerto Rico (Watlington 2002), Cuba (under harvest since 1995, Berovides et al. 2000) and Colombia (San Andres and Gorgona Island; Forero et al. 2006, Velasco and Balaguera-Reina 2018).
Update : 11 April 2017