I don't think I had ever heard of the kayo kyoku equivalent of a public service announcement before. Beginning with the Morse code tapping for the title itself, Pink Lady's Mie and Kei set off to warn all of the ladies out there about the dangers of that band of wild animals lurking and pouncing nearby...namely, men. But they do it so cheerfully. It's rather nostalgic listening to this one since it seems as if the tables have been turned somewhat of late.
"S.O.S." was Pink Lady's 2nd single from November 1976, and of course, it was written and composed by the team of Yu Aku and Shunichi Tokura（阿久悠・都倉俊一）. The song became the duo's first No. 1, doing so on Valentine's Day 1977 of all times....a bit of a musical buzzkill for the guys, perhaps. Also, according to the Oricon charts, the song would end up as the 8th-ranked song for the year, selling about 650,000 records, although Pink Lady's producing studio, then-called Victor Music Industries, gave a figure of 1.2 million according to J-Wiki. The single also belonged to their first album, "Pepper Keibu" （ペッパー警部...Detetctive Pepper）which came out in July 1977.
Another interesting point about the song is the intro of that Morse code. If you had never heard the original single, you wouldn't have heard the tapping since the authorities were concerned about it causing undue alarm on the radio or on the TV shows. It was politely excised from the performances.
However, Pink Lady wasn't my first source of a song titled "S.O.S." That honour has to go to the Swedish band ABBA from about a year previously. I mention them since I used to hear the song all the time on all those old K-TEL LP commercials. And that little bit of cultural Sweden has also entrenched itself deep into the Japanese pop cultural psyche, although perhaps not to the extent of The Carpenters.