Dear Chelsea,

I am not an expert on marine mammals, but in my understanding they are one of the least aggressive life forms on the planet. It is a very interesting question, but I doubt that you will find any information about aggression towards humans for this or related species. A quick google scholar search didn't yield anything even close to what you are asking. Good luck anyways!

Georg

Hi Chelsea,

you may know King, J.M. and J.T. Heinen. 2004. An assessment of the behaviors of overwintering manatees as influenced by interactions with tourists at two sites in central Florida, Biological Conservation 117:227-234.?

They studied human-manatee in-water encounters. Even though snorkelers often behaved inappropriately, manatee responses ranged from tolerance to avoidance. They do not seem to respond aggressively. In contrast, touch (and food-provisioning!) often elicits risky behaviors among dolphins during encounters with human swimmers/divers/waders. Recently, I studied (non-provisioned) grey seals during swims with humans, and they initiated high rates of risky behaviors. So, sirenians might be the peacemakers among marine mammals during encounters with swimmers. However, I would agree with Phillip's statement: there is definitely a potential to initiate aggressive behaviors, similar to intraspecific interactions.

Hi Chelsea,

Your question is interesting and stems from misguided suggestions that manatees can be aggressive towards humans. This is not true. Generally, if manatees are perceived as aggressive it is usually because they are powerful animals that when they encounter humans (or other threats) they can accidentally capsize water vessels when they react or flee in an attempt to seek clear evacuation routes usually into deep water. All manatees in most places are very stealthy and secretive in their movements, so they are very difficult to detect. Historically, this behavior has protected them from being detected by hunters, so most manatees throughout their range have little trust for humans. This lack of trust is being extinguished only in Florida, where manatees have been protected for decades. Also, manatees are herbivores (and only have molar dentition) and any behavioral aggression they may display is usually related to mating activities, where males compete in competition to improve breeding chances with receptive females. These mating herds can be rambunctious. Mothers will sometimes head butt their calves in a disciplinary fashion to try to keep them from getting into dangerous situations. There has been quite a bit of antidotal information published on manatee behaviors. For Florida, start with Hartman (1976) and work through the huge amount of documentation.

Hartman DS (1979) Ecology and Behavior of the Manatee (Trichechus manatus) in Florida. The American Society of Mammalogists, Special Publication Number 5. 153 pp.

Reynolds JE III, Odell DK (1991) Manatees and Dugongs. Facts on File Press, New York, New York. 192 pp.

Reep RL, Bonde RK (2006) The Florida Manatee: Biology and Conservation. University Press of Florida, Gainesville, Florida. xvi + 189 pp.

I hope this helps,

Bob Bonde

Hi everyone,

Thank you for all your insight and suggestions. I asked the question because I'm currently prepping a short manuscript documenting my unusual encounter with an aggressive mating herd of manatees in Puerto Rico, while conducting some fish collections on SCUBA. I was searching the literature for any similar events and found nothing. Thank you for your suggestions, and if anyone knows any other information that may be related to incidents such as this, please feel free to direct it to this post.

Have you contacted Sirenian International?

https://www.facebook.com/groups/sirenian

http://www.sirenian.org

Cary Self-Sullivan is most resourceful.

In case anyone would like to read about this encounter with manatees, here is the note: Article Unusual aggressive behavior encountered by divers from Antil...

We received lots of great feedback from reviewers and from others in the marine mammal field and are glad we could provide some insight to other divers.