Breaching, the act of a whale propelling its massive body out of the ocean and crashing back down, is one of nature’s most impressive displays. This powerful acrobatic act captivates observers and highlights the remarkable capabilities of marine mammals. Scientists are intrigued by the reasons and timing behind this behavior, as understanding it offers insights into their complex lives beneath the waves.
What is Breaching?
Breaching describes a whale launching itself partially or entirely out of the water. The whale builds speed underwater, thrusts upwards, and often twists its body before re-entering with a resounding splash. A “full” breach means more than half the body clears the surface, while a “half breach” involves less. This behavior differs from a “lunge,” a less intentional leap often associated with feeding. The loud sound created upon re-entry travels far underwater.
Why Whales Breach
One primary theory suggests whales breach for communication. The loud splash generated upon re-entry can be heard over long distances underwater, serving as a signal to other whales. This communication is particularly useful in noisy or rough ocean conditions where underwater sounds, like whale songs, might not travel effectively. Whales may use breaching to announce their presence, signal excitement, or warn others of potential threats.
Breaching also serves social purposes, including attracting mates. During breeding seasons, male whales may breach to display strength and agility, signaling their fitness to potential partners. Increased breaching activity is observed when groups of whales interact or new whales join a group, suggesting a role in social bonding or establishing social hierarchies.
Another reason for breaching is to dislodge external parasites. The forceful impact helps remove barnacles, whale lice, and other organisms that attach to their skin, which can cause irritation or increase drag. Additionally, breaching may allow whales to scan their surroundings from an elevated perspective, observing distant landmarks or marine activity. It is also thought that breaching could be a form of play, especially among younger whales, helping them develop physical skills and coordination.
Timing and Context of Breaching
Breaching often occurs more frequently during migration and breeding seasons. For instance, humpback whales breach more often in warmer breeding grounds, even while fasting. This aligns with the theory of breaching as a mating display.
While no strict daily pattern exists, breaching is frequently observed during social interactions. When whale groups are farther apart, breaching may increase for long-range communication. Conversely, some studies indicate a decrease in breaching when groups are closer, as they rely on other communication forms. Breaching can also be observed during feeding events; though not a primary feeding technique, it can be part of cooperative hunting strategies like bubble-net feeding.
Factors Influencing Breaching Frequency
External and environmental factors influence breaching frequency. Water conditions, such as wind and waves, play a role; humpback whales may breach more vigorously on windier, choppier days. This could relate to communication, as a louder splash is more effective in noisy waters.
The presence of other whales also affects breaching frequency. It is often more common in groups, potentially serving as a non-verbal signal. Conversely, solitary whales may breach more often than those in small groups. Due to the high energy cost, larger whale species, like blue whales, generally breach less frequently than smaller, more agile species such as humpback whales. Human activity, such as the presence of boats, might also influence breaching, with some evidence suggesting whales breach less often near vessels.