Evolution Link Between Bat Size and Sonar Abilities

Greg Howard
16th April, 2024

Evolution Link Between Bat Size and Sonar Abilities

Key Findings

  • Study from Universidad Rey Juan Carlos shows larger bats use lower frequency echolocation calls
  • Differences found in echolocation between bats that emit calls through their nostrils versus their mouths
  • Bat body size evolution is linked to changes in echolocation call features, suggesting co-evolution
Understanding the relationship between a bat's body size and its echolocation abilities is a key piece of the puzzle in bat biology. Echolocation is the system bats use to navigate and find food in the dark, emitting sounds and listening for the echoes that bounce back from objects. This ability is not only fascinating but also varies widely among the more than 1,400 species of bats. Researchers from Universidad Rey Juan Carlos have conducted a study[1] to examine how the frequency, bandwidth, and duration of echolocation calls scale with body mass in bats, and whether these relationships differ between bats that emit calls through their nostrils (nasal emitters) and those that emit calls through their mouths (oral emitters). The study analyzed data from 314 bat species, using advanced statistical methods that take into account the evolutionary relationships between species. This approach is crucial because it helps to avoid misleading results that might arise if one assumes that all bat species are independent of one another. The methods used in this study are particularly robust, employing Bayesian statistics, which allow for a more nuanced interpretation of data based on probability. One of the intriguing findings of this research is the confirmation that larger bats tend to use lower frequency calls. This relationship, known as allometry, is not uniform across the entire order of bats. Notably, the study found differences in the scaling patterns of echolocation call features between nasal and oral emitting bats. These differences could be linked to the various adaptations that have evolved to suit the diverse ecological niches bats occupy and the sensory challenges they face. The study's findings also suggest that changes in body size throughout bat evolution may have been coupled with changes in echolocation parameters. This is an important insight, as it could indicate that as bats evolved into different sizes to adapt to different environments, their echolocation systems evolved in tandem. This co-evolution of body size and echolocation characteristics is a key piece of evidence in understanding how bats have become such a diverse and successful group of mammals. Previous research has shown that bats are highly diverse in both their physical characteristics and their behaviors[2]. They use a variety of signals for communication, relying heavily on sound and smell due to their nocturnal nature. The complexity of bat communication, particularly through social calls, is well-documented[2]. The current study adds another layer to our understanding by showing how these communication systems are related to physical size. The evolution of bat echolocation has been a topic of debate, and recent studies have provided evidence that echolocation may have evolved independently in different bat lineages[3][4]. The current study contributes to this discussion by suggesting that as bats evolved in size, their echolocation calls evolved as well. This supports the idea that echolocation is a dynamic trait within bat evolution, rather than a static one. Additionally, the discovery of a new early Eocene bat species, Vielasia sigei, which exhibits both primitive and advanced features, has provided insight into the early stages of bat evolution[5]. The findings from the Universidad Rey Juan Carlos study build upon this by demonstrating that echolocation features are closely tied to body size, which may have implications for how we understand the development of echolocation in the bat lineage. In conclusion, the study from Universidad Rey Juan Carlos provides valuable evidence that body size and echolocation call characteristics are interrelated in bats, with distinct patterns emerging between nasal and oral emitters. This research not only enhances our understanding of bat biology but also offers a window into the evolutionary processes that have shaped the sensory systems of these remarkable creatures. As we continue to uncover the secrets of bat echolocation, we gain a greater appreciation for the complexity and adaptability of this unique order of mammals.

Animal ScienceEvolution


Main Study

1) Correlated evolution between body size and echolocation in bats (order Chiroptera)

Published 15th April, 2024


Related Studies

2) Social communication in bats.


3) Nonecholocating fruit bats produce biosonar clicks with their wings.


4) Molecular evidence regarding the origin of echolocation and flight in bats.

Journal: Nature, Issue: Vol 403, Issue 6766, Jan 2000

5) A 50-million-year-old, three-dimensionally preserved bat skull supports an early origin for modern echolocation.


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