Morphology, Behaviour and Evolution of Gallotia Lizards from the Canary Islands.

We summarize, here, the results from several studies conducted over many years on several endemic species of lizards (genus Gallotia) from the Canary Islands. Quantitative analyses show clear differences both among the species of every island and populations within each species. Sexual dimorphism exists in all analysed species, and a phylogenetic analysis shows that the degree of dimorphism did not change along the evolutionary history of the Canary Islands: species with large and small body sizes have a similar degree of sexual dimorphism, with male body size changes closely following those undergone by females. In G. caesaris (from El Hierro and La Gomera islands) and in G. stehlini (from Gran Canaria), longer hind limb length was correlated with more open habitats. Within most species, males are more conspicuous than females, mainly in terms of body size, behaviour and coloration pattern. Lateral colour spots are blue in most species and green in others. In G. galloti from Tenerife, male lateral spots have larger spot areas and percentage of reflectance in the ultraviolet/blue part of the spectrum than females. This trait shows a monthly variation along April to July, both in males and females, its magnitude being larger in May-June. Behaviour analysis, especially in the last species, shows a great diversity in behaviour patterns, and analysis of intrasexual male competition revealed that contest outcome depends on several morphological and colouration characteristics but mainly on the individual's behaviour. Detailed behavioural analyses were useful for managing a few captive individuals of the highly endangered G. bravoana from La Gomera island. Experimental analyses of some behaviours in the endemic Hierro island lizard (G. simonyi, in danger of extinction) show that individuals may learn to recognize predator models and increase their running speeds with training.

Daily running trials increase sprint speed in endangered lizards (Gallotia simonyi).

Due to increasing number of animal species in danger of extinction, captive breeding of individuals has become a necessary procedure for many recovery programs. As specimens born and raised in captivity during several generations may not develop some behavioral and performance aptitudes properly, several types of training are useful to apply before releasing them into the wild. We present here the results of experiments aiming to detect the effect of daily running trials in young males of the endangered lizard (Gallotia simonyi) from El Hierro (Canary Islands). We made individuals run in a racetrack twice every day, for five days a week between the end of July and the end of September. We filmed all running trials and calculated running speed for each individual dividing the distance run by the time used. Running speed did not correlate with body condition of the lizards but there was variation in running speeds of some individuals with similar body conditions. Running speed of lizards used in the experiments significantly increased along the whole trial period. By contrast, mean running speed did not change significantly in a control group, participating twice in running trials, one at the beginning and the other at the end of the experimental period. From these results we suggest that locomotor training contributed to increasing final running speeds of experimental lizards.

Social interaction analysis in captive orcas (Orcinus orca).

The management of socially complex species in captivity is challenging. Research on their social behavior improves our understanding of interactions in captive animals and captive-group management. We conducted a detailed analysis of social relationships shown by the orcas kept at Loro Parque zoo and their tendency to reconcile after aggressive episodes. Affiliative interactions were the most frequent social activities compared to agonistic or sexual interactions. Within affiliative behaviors, we documented the pattern "gentle tongue bite", where an animal touches the other's tongue with his teeth but does not bite it. Affiliative interactions between a specific pair of orcas occurred significantly more often than expected by chance, and together with low levels of agonistic interactions, indicated particular affinity between some individuals. The most frequently observed low-level agonistic relationship was that of the two older males (Tekoa-Keto); however, they also showed frequent sexual and affiliative interactions. Sexual-like behaviors (pursuit, mount, and penis between males) were found in both sexes. Finally, the observed corrected conciliatory tendency (31.57%) was within the range described for other primate and cetacean species. This study provides a systematic way to assess social interactions as well as conflict management strategies in cetaceans housed in zoos and zoo-like facilities and may help to improve animal welfare and management of animals in controlled environments.

Predator avoidance training of the endangered lizard from El Hierro (Canary Islands): A new management strategy before reintroduction into the wild.

Animals raised in captivity during several generations may not express appropriate antipredator behaviour when reintroduced into the wild. Here we present the results of experiments to enhance behavioural responses to predators in adult males of the endangered lizard Gallotia simonyi (El Hierro, Canary Islands). Individuals were subjected to a training procedure (control, pre-training, training and post-training phases) using stuffed specimens of a kestrel and a cat as predators. We filmed all trials and compared relative durations of the more common behaviour patterns shown by lizards, both among experimental phases and before and after presentation of the stuffed predator. Locomotion and Basking were significantly reduced in the training and post-training trials and also after stimulus presentation, suggesting that the training protocol induced lizard avoidance over both predator models. To our knowledge, this is the first time lizards have been trained to show antipredator avoidance and our results provide the basis for a new management strategy that could be useful for reintroduction of captive-bred individuals of endangered species.

Effects of testosterone on morphology, performance and muscle mass in a lizard.

Because sexual selection pressures are high in sexually dimorphic organisms, morphological, physiological and performance traits are often studied in a sexual selection context. The proximate mechanisms underlying evolutionary change in these traits, however, remain largely unstudied. Here, we examined the role of steroids in shaping morphology and physiological performance in males of a sexually dimorphic lizard (Gallotia galloti). We compared morphology and physiological performance of males with experimentally elevated testosterone levels to sham-operated males. Before surgery, inter-individual variation in plasma testosterone levels correlated positively with bite force capacity. Administration of exogenous testosterone resulted in an increase of the mass of both jaw closing and locomotory muscles compared with sham-operated individuals, but the responsiveness varied considerably among muscle groups. In contrast to our expectations, the dramatic testosterone-induced changes in muscle masses did not result in concordant changes in bite force performance or sprint speed.

Behavior as a tool for welfare improvement and conservation management in the endangered lizard (Gallotia bravoana).

The study assessed the behavior of Gallotia bravoana (La Gomera, Canary Islands, one of the world's most threatened reptiles) to facilitate management decisions and improve welfare during initial stages of a species' recovery plan. The study analyzed--and remote-controlled video cameras filmed-the behavior of lizards housed in 3 outdoor enclosures, from May to September 2000. Daily activity showed a bimodal or unimodal pattern, all specimens basking more during June, with the largest male was the most active. Adults ate a higher percentage of vegetable items; subadults, a comparatively larger proportion of larvae and adult insects. The study analyzed individual compatibility; all interacted during 2 short periods. Aggression occurred mainly between males; because most directed high-intensity aggression toward a specific lizard, the study recommended isolating this lizard in a separate enclosure. The study recommended keeping 2 male-female pairs, who demonstrated social tolerance, as breeding pairs in separated terraria. Typical courtship behavior (head-bob sequences) occurred mainly during July, with highest frequency by the oldest male. Behavioral assessment provided data for improving the individuals' welfare in the enclosures and to select specific pairs for breeding.