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Some species exhibit behavioral plasticity by altering their aggressive behavior based on their opponent. Atlantic spotted dolphins (Stenella frontalis) and bottlenose dolphins (Tursiops truncatus) are two sympatric species resident to the northern Bahamas. We examined whether groups of adult male spotted dolphins demonstrated behavioral plasticity during two different types of aggressive interactions. We described and compared the types of aggressive behaviors used during intraspecific aggression and interspecific aggression with bottlenose dolphins. Between the years 1991-2004, twenty-two aggressive encounters (11 intraspecific (spotted only), 11 interspecific (spotted vs. bottlenose)) were behaviorally analyzed. Twenty-three specific aggressive Behavioral Events, further grouped into three Behavioral Types, were examined throughout these encounters. Similarities and differences in the use of the Behavioral Types occurred during intra- and interspecific aggression. Groups of male Atlantic spotted dolphins altered their behavior during aggressive encounters with male bottlenose dolphins. Spotted dolphins increased their use of the Pursuit Behavioral Type and did not use the Display Behavioral Type significantly more than the Contact Behavioral Type during interspecific aggression. The increased use of a more overt and energy intensive Behavioral Type, Pursuit, suggests that Atlantic spotted dolphins altered their behavior during aggressive encounters with bottlenose dolphins to compensate during fights with a larger species and/or to effectively communicate with a different species.

Demographic changes can result in alterations of social structure and behavior which in turn may affect survival, reproduction, or movement and may influence how populations respond to changes in the environment. In 2013, 52 Atlantic spotted dolphins (Stenella frontalis) left Little Bahama Bank (LBB) and immigrated into a resident group of spotted dolphins on Great Bahama Bank (GBB). Initially there was little interaction and two distinct social clusters delineated by residency status. Here we describe the social structure of the dolphins on GBB between 2015-2020.Analyses were conducted with SOCPROG 2.9 and coefficients of association were nonrandom. The number of associations between LBB and GBB individuals increased, and standardized lagged association rates indicated continued associations over time. Modularity analysis showed one community without clear social clusters, although there were preferential associations within the original communities. Multiple Regression Quadratic Assignment Procedure indicated that sex, age, and residency status were good predictor variables that explained the patterns of the association indices. Male alliances were present between LBB, GBB, and LBB/GBB males. New and old relationships are influencing the social restructuring of this community. This

Cetacean mixed-species groups are common around the world, but little is known about how and why they occur. Tursiops truncatus (Common Bottlenose Dolphin) and Stenella frontalis (Atlantic Spotted Dolphin) are delphinidae species that have been sighted, separately, along the southeast coast of Florida. Although these species are observed interacting together in other portions of their range, this is the first report of a known mixed-species group of Atlantic Spotted Dolphins and Common Bottlenose Dolphins off the southeast Florida coast. We observed both foraging and social behaviors using a DJI Mavic Pro 2 drone. The function of mixed-species groups is understudied, yet Florida may provide opportunities for future research.