I learned this song from my mother, Natercia Pires do Prado, when I was 6 or 7. Written by the great Waldemar Henrique, from Belém do Pará, with lyrics by Antonio Tavarnard, it talks about Tajapanema (the plant of sadness). This plant “weeps” when something bad is about to happen. This song explains what happened to a young girl who left her village on the Coastal boat.  As the legend goes, the manatee comes out of the Amazon River as a seductive and irresistible young man... to steal heart and all-good sense from beautiful innocent girls. 
 

Lyrics

Tajapanema chorou no terreiro
E a virge morena fugiu no costeiro
Foi boto, sinhá, foi boto, sinhô
Que veio tentar e a moca levou
No tar dançará, aquele doutor
Foi boto, sinhá! foi boto, sinhô!
 
Tajanema se pos a chorar
Quem tem filha moça é bom vigiar
O boto num dorme no fundo do rio
Seu dom é enorme
Quem quer que o viu
Que diga, que informe, se lhe resistiu
O boto num dorme no fundo do rio
 
Translation:
Tajapanema cried in the yard
And the virgin brunette ran off on the boat
It was the manatee, m'am, it was the manatee, sir.
He came to tempt the girl and take her
At the dance by the river, that well-dressed guy,
It was the manatee, sir, it was the manatee, mam.
 
Tajapanema cried in the yard   
You'd better keep an eye on your young daughters
The manatee doesn't sleep at the bottom of the river
His gift is huge whoever has seen it
Must tell, must inform if it can be resisted.
 
Maguinha, vocals
Douglas Lora, guitar