Lots of surf and wind on February 11th!
Aloha,
With the active winter storm warnings in the forecast, we knew on Sunday that we wouldn’t be able to operate safe and comfortable cruises on Monday, so we cancelled in advance. Good thing we did, because you can see in the photo what awaited us on Monday morning!
With no whale sightings to report, I’m going to take advantage of the blog space to explain a bit more about that intriguing and mystifying Humpback song.
Of course, no one knows for sure why male Humpbacks sing those long, complex songs we hear through our hydrophones (or while in the water) during the wintertime in Hawaii, but there is a lot of ongoing research analyzing the behaviors of the singers, and how others in the population react to them.
Here’s some of what we know about the song so far:
- Not every Humpback sound we hear in winter is part of the “song”. All Humpbacks vocalize.
- Only male Humpbacks have been observed singing, and when they sing, they’re stationary.
- For the most part, they only sing during the breeding season (though songs may be heard in late fall in the feeding grounds, presumably coinciding with an increase in hormonal activity prior to mating season).
- All singers in a particular population are singing basically the same song, though that song is continually evolving (when a male “ad-lib’s” a new phrase, other males will add that phrase to their song – they drop the same phrases too).
- Females have never been observed approaching a singer.
- When another male approaches a singer they may interact briefly and then split up and swim towards other singers, where brief interaction occurs before splitting up and joining yet again with other singers.
So, since females apparently aren’t approaching singers, the song probably isn’t a true “mating song”. Also, since each male sings basically the same song, it probably isn’t sung to attract females (individuals aren’t producing anything substantially different — at least to our ears – so why would a female choose one song or singer over another?). Based on these facts, along with the observations of male Humpbacks’ interactions with each other while singing, some researchers theorize that the song is sung as a way for the males to organize themselves socially.
A couple of years ago researchers discovered a whole new layer of complexity to the Humpback song – very low frequency pulses (think of the way sound is reverberated through very loud bass speakers). We aren’t completely sure of the purpose of these sounds. Since these sounds have been recorded when many males are chasing a single female, they may be part of the mating ritual. It’s even been theorized that the females are the ones who are producing these sounds — as a way to differentiate from the males “songs” … perhaps they are trying to communicate something to other females who are further away. If you’d like to read more about this low frequency sound and how it was discovered, click here.
If you’d like to listen to a little clip of the sound, click here. Unless you have very good speakers, your best bet to hear the sound clearly is to put on some headphones and listen for the heartbeat-like pulsing noise.
If you’re interested in the Humpback song, I invite you to to keep reading our Facts of the Day…I’ll post more info throughout the rest of the season (e.g.: decibel levels, theories about song organization and transmission…and even other places you can hear the Humpback song besides the ocean). And if you have specific questions about the song (or about the Humpbacks in general), please feel free to contact me here. I’ll do my best to respond to you directly and in this blog.
Looking forward to hearing from you!
Mahalo,
Claire