A whiff of
the past
Ambergris isn’t just an ingredient of luxury
perfumes, finds Claire Ainsworth
T
HEY say, where there’s muck, there’s
brass. Anyone who has stumbled
upon ambergris will confirm this. The
weathered whale excrement is extremely rare,
but it can be found on beaches in many parts of
the world. It is unprepossessing: dusty grey or
brown with the faintest whiff of earth and sea,
mixed with something unfathomably animal.
Yet this stuff is so prized by perfume-makers
that a lump the size of a human head could
fetch you £50,000 or more.
Traditionally used to boost the staying
power of scents, these days a synthetic
alternative means that ambergris is found
only in some luxury fragrances. But now
scientists have discovered that it harbours
another treasure. Adrift in the oceans for
decades, even centuries, before washing
ashore, each lump is a message in a bottle from
a long-departed whale. It holds clues about
the lives of these animals before whalers came
to plunder them. “There’s really quite exciting
potential to look at the impact of whaling
on whale health and diversity,” says Ruairidh
Macleod at the University of Cambridge.
Ambergris also contains historical
information about the oceans, especially
the marine species foraged by the whales that
produce it. It could even give insights into how
these animals might respond to the challenges
they face as a result of climate change.
Ambergris usually makes landfall after
a long voyage, originating as black, waxy
lumps in a sperm whale’s colon. Nobody knows
exactly why it forms. It may encase the sharp
beaks of the squid that the whales prey on to
stop them damaging the gut, or it may simply
be a quirk of metabolism. The fresh stuff,
reeking of faeces, has much less value than
ambergris matured by a long soak in the sea.
This latter form, known as jetsam ambergris,
is composed chiefly of ambrein, an organic
chemical capable of stabilising volatile scents,
which is what made ambergris so sought-after
by perfumiers. But it is ambrein’s ability torepel water and resist decay that first drew
the attention of Macleod and his Cambridge
colleague Matthew Collins. They realised that
ambergris could encase DNA and protect
it from the elements. What’s more, it could
do this for centuries: in 2019, a team led by
chemist Steven Rowland at the University of
Plymouth, UK, carbon-dated a collection of
ambergris to show that some lumps had been
in the environment for around 1000 years.Sperm-whale speciality
In a preliminary study, Macleod and his
colleagues succeeded in sequencing stretches
of DNA from Rowland’s ambergris collection.
This confirmed what many had suspected
but never been able to show, namely that
ambergris is produced by sperm whales. Now,
the researchers want to sequence the DNA in
ambergris more thoroughly, to read the history
hidden in the whales’ genomes. Studies of
ancient DNA from other marine mammals
show this approach can paint a surprisingly
detailed picture. For example, in 2019, team
member Morten Tange Olsen at the University
of Copenhagen, Denmark, and his colleagues
combined analyses of DNA from walrus bones
with historical and archaeological information
to explore why walruses disappeared from
medieval Iceland. This revealed the existence
of a genetically unique population that appears
to have been hunted to oblivion by Norse
settlers during the 11th and 12th centuries.
”What really surprised me is how far back
in time humans have had an impact on
marine ecosystems,” says Tange Olsen.
In the 20th century, commercial whalers
slaughtered at least 3 million whales. Studies
of ambergris DNA could help researchers
assess the relative sizes of pre-whaling sperm
whale populations and their genetic diversity.
Comparison of ancient whale DNA with
modern samples might also hint at how
PE natural selection has shaped these animals.
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56 | New Scientist | 18/25 December 2021