California Sea Lion (Zalophus californianus, Lesson 1828)

Hernández‐Camacho, Claudia J.; Pelayo‐González, Lili; Rosas‐Hernández, Martha P.

doi:10.1007/978-3-030-63177-2_7

Cited by 4 publications

(8 citation statements)

References 91 publications

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“…Its reproductive colonies range spans from the Channel Islands in California, USA, to Margarita Island on the west coast of the Baja California peninsula and in the Gulf of California, Mexico (García‐Rodríguez & Aurioles‐Gamboa, 2004; Lowry et al, 1990; Orr et al, 2011). Thus, it feeds in different habitats throughout its distribution, and the composition of its diet varies depending on geographical availability (García‐Rodríguez & Aurioles‐Gamboa, 2004; Hernández‐Camacho et al, 2021; Orr et al, 2011; Rosas‐Hernández et al, 2018).…”

Section: Discussionmentioning

confidence: 99%

Mechanical properties of the California sea lion (Zalophus californianus) and northern elephant seal (Mirounga angustirostris) lower jaws explain trophic plasticity

Nieto-Miranda

Aguilar-Medrano

Hernández‐Camacho

et al. 2023

The Anatomical Record

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The fossil record of pinnipeds documents a suite of morphological changes that facilitate their ecological transition from a terrestrial to an aquatic lifestyle. Among these is the loss of the tribosphenic molar and the behavior typically associated with it in mammals: mastication. Instead, modern pinnipeds exhibit a broad range of feeding strategies that facilitate their distinct aquatic ecologies. Here, we examine the feeding morphology of two species of pinnipeds with disparate feeding ecologies: Zalophus californianus, a specialized raptorial biter, and Mirounga angustirostris, a suction specialist. Specifically, we test whether the morphology of the lower jaws facilitates trophic plasticity in feeding for either of these species. We used finite element analysis (FEA) to simulate the stresses during the opening and closing of the lower jaws in these species to explore the mechanical limits of their feeding ecology. Our simulations demonstrate that both jaws are highly resistant to the tensile stresses experienced during feeding. The lower jaws of Z. californianus experienced the maximum stress at the articular condyle and the base of the coronoid process. The lower jaws of M. angustirostris experienced the maximum stress at the angular process and were more evenly distributed throughout the body of the mandible. Surprisingly, the lower jaws of M. angustirostris were even more resistant to the stresses experienced during feeding than those of Z. californianus. Thus, we conclude that the superlative trophic plasticity of Z. californianus is driven by other factors unrelated to the mandible's tensile resistance to stress during feeding.

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Section: Discussionmentioning

confidence: 99%

Mechanical properties of the California sea lion (Zalophus californianus) and northern elephant seal (Mirounga angustirostris) lower jaws explain trophic plasticity

Nieto-Miranda

Aguilar-Medrano

Hernández‐Camacho

et al. 2023

The Anatomical Record

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“…Their diet, reproductive and foraging behavior, and some life history traits (e.g. annual survival rates, sexual maturity average age, lactation duration) are shaped by environmental conditions surrounding individual colonies (Bohórquez-Herrera et al 2014; López-Alvirde 2014; Rosas-Hernández et al 2018; Hernández-Camacho et al 2021). For example, air temperatures that California sea lions are exposed to on the Pacific coast of the Baja California peninsula versus the Gulf of California can differ during summer, with temperatures >30 °C in the Gulf of California (Roden 1964; Roden and Emilson 1980; Bray 1988; CONANP 2000; Trasviña-Castro and González-Rodríguez 2013) and <25 °C on the Pacific coast (Ramírez and Fleischer 1987).…”

mentioning

confidence: 99%

“…Differences in life history traits and environmental conditions exist between California sea lions from the Pacific coast of the Baja California peninsula and those from the Gulf of California off of the coast of mainland Mexico (Szteren and Aurioles-Gamboa 2011; López-Arvide 2014; Rosas-Hernández et al 2018; Pelayo-González et al 2021a, 2021b; Hernández-Camacho et al 2021), and geographic isolation between populations may be accelerating their genetic divergence (González-Suárez et al 2009). Previous genetic studies indicated that California sea lions are separated into 5 subpopulations (Fig.…”

mentioning

confidence: 99%

“…1): temperate Pacific (Channel Islands of California, United States); tropical Pacific (Pacific coast of Baja California peninsula; PC); and the northern, central, and southern groups within the Gulf of California (González-Suárez et al 2009; Schramm et al 2009). Currently, estimates of total numbers of California sea lions range from 327,157 to 334,205 individuals, of which 80% are in the United States, 14% on the Pacific coast of the Baja California peninsula, and only 6% in the Gulf of California (Hernández-Camacho et al 2021). Similar results indicating population isolation resulting from environmental and climatic variability have been reported for other pinniped species (Brunner 2004; Drehmer 2005; Hoffman et al 2006; Túnez et al 2007; Artico et al 2010; Túnez et al 2010; Feijoo et al 2011; Oliveira et al 2017).…”

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confidence: 99%

“…1). Analyses show that most colonies within these subpopulations are experiencing declines in population size, with only a few colonies that are stable and 1 increasing (Elorriaga-Verplancken et al 2015; Hernández-Camacho et al 2021). Recent studies show that birth rates and population totals may be linked to a decrease in prey abundance (Adame et al 2020; Pelayo-González et al 2021a, 2021b).…”

mentioning

confidence: 99%

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Skull shape and size changes in different subpopulations of the California Sea Lion (Zalophus californianus) in Mexico

Aguilar Medrano,

Cruz Escalona,

Payán Alcacio

et al. 2023

Journal of Mammalogy

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California sea lions (Zalophus californianus) are distributed along the Gulf of California and northeastern Pacific coast. Genetic studies have suggested the existence of 3 to 4 subpopulations in Mexico—1 on the Pacific coast of the Baja California peninsula (PC) and 3 in the Gulf of California—but the extent of this divergence is unclear, and it remains unknown if these subpopulations are morphologically distinct. In this context, we analyzed variation in skull size and shape of adult males between 5 and 13 years of age among 2 (north and central) of the 3 subpopulations of Z. californianus from the Gulf of California and the PC in Mexico. However, since the sample sizes for the 2 subpopulations in the Gulf of California were small, we merged all samples into 1 that we called the Gulf of California (GC) subpopulation. Artificial neural networks and geometric morphometrics were used to analyze skull images to quantify the extent to which these geographically separated subpopulations are undergoing morphological divergence. Our results find no significant differences in size in any view between the 2 subpopulations, but significant differences in the morphology of the dorsal, ventral, and lateral views of the skull between the 2 subpopulations. Overall, Z. californianus from the GC subpopulation have wider and lower skulls, extended back and outward with a more voluminous (bulky) nuchal crest, and narrow rostrum in comparison with skulls of Z. californianus from the PC subpopulation. Results concur with a previous genetic-based study, demonstrating that Z. californianus from both subpopulations in Mexico are diverging in their skull morphology and perhaps suggesting that they are experiencing different evolutionary pressures.

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Unraveling the gut microbiota of Mexican pinnipeds: the dominance of life histories over phylogeny

Pacheco-Sandoval,

Schramm,

Heckel

et al. 2024

Appl Environ Microbiol

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Studying how phylogeny influences the composition and functions of microbiotas within animal hosts is essential for gaining insights into the connection between genetics, ecology, and health in the animal kingdom. However, due to limited comprehensive studies, this influence remains unclear for many wild mammals, including Mexican pinnipeds. We employed 16S rRNA gene deep-sequencing to investigate the impact of phylogeny on the gut microbiota of four pinniped species inhabiting Mexican shores: the Pacific harbor seal ( Phoca vitulina richardii ), the northern elephant seal ( Mirounga angustirostris ), the California sea lion ( Zalophus californianus ), and the Guadalupe fur seal ( Arctocephalus philippii townsendi ). Our results indicated that factors such as diets and shared life histories exerted more influence on microbiota composition than phylogeny alone. Notably, otariid species sharing similar life histories displayed greater microbiota similarity than phocids, which have distinct life histories and fewer microbiota similarities. Furthermore, harbor seals have more microbial similarities with the two otariid species than with elephant seals. Of particular concern, we observed a higher abundance of potentially pathogenic bacteria (e.g., Photobacterium damselae and Clostridium perfringens ) in harbor seals and Guadalupe fur seals compared to other pinnipeds. This finding could pose health threats to these species and nearby human populations. IMPORTANCE Pinnipeds in Mexico host microbial communities that remain understudied. While several factors can influence microbiota composition, the role of phylogenetic relationships among these pinnipeds remains unclear due to limited knowledge of the microbiota in certain species. This study aimed to fill this gap by characterizing the composition and function of the gut microbiota in the four pinniped species that occur in Mexico. Our analysis reveals that shared diets and life histories contribute to similarities in the composition of gut microbial communities. This study also highlights the potential differences in the metabolic capabilities and adaptations within the gut microbiota of pinnipeds. Understanding how phylogeny impacts microbial communities enhances our insights into the evolutionary dynamics of marine mammals.

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California Sea Lion (Zalophus californianus, Lesson 1828)

Cited by 4 publications

References 91 publications

Mechanical properties of the California sea lion (Zalophus californianus) and northern elephant seal (Mirounga angustirostris) lower jaws explain trophic plasticity

Mechanical properties of the California sea lion (Zalophus californianus) and northern elephant seal (Mirounga angustirostris) lower jaws explain trophic plasticity

Skull shape and size changes in different subpopulations of the California Sea Lion (Zalophus californianus) in Mexico

Unraveling the gut microbiota of Mexican pinnipeds: the dominance of life histories over phylogeny

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