Context

In classical mythology, Thetis is Nereid or sea-nymph and the mother of the hero Achilles. Like other Nereids, Thetis has the power to change shape and to prophesise. After hearing a prophecy that Thetis would bear a child who was greater than his father, Zeus, fearing a rival, made Thetis marry a mortal.

Themes

fluidity, pursuit, violence, maternity

Language/imagery

Duffy uses an array of phonological devices in this poem; the use of similar sounds such as end rhymes (man/sang), assonance (roar, claw, paw, floored) and sibilance (shopped/shape, size/snake) occurs within stanzas and then changes with each new stanza as Thetis adopts a different form.

There are intextual references in the second stanza: 'shouldered the cross of the albatross' which combines images associated both the Christian story of the crucifixion with that of the albatross; in the Romantic poem The Ancient Mariner, killing an albatross brings bad luck.

The forms that Thetis adopts and the images used to depict her are natural, either animal or elemental: 'bird', 'wings', 'snake', 'claw', 'paw', 'gore', 'mermaid', 'eel', 'dolphin', whale', 'racoon', 'skunk', 'weasel', 'bat', 'wind', 'gas', 'clouds', 'flame'.

In contrast the images that symbolise the men in pursuit of her are of those of tools and weapons: 'crossbow', 'gun' 'knives' 'fighter plane,' and of violence 'fist' 'strangler'.

The final stanza represents a resolution of sorts. The language is associated with desire but also danger, 'my kisses burned', however the groom wears 'asbestos', an unromantic image of a fire-proof and carcinogenic material; this hunter not only resists her, he is also potentially fatal. After this revelation comes the volta: 'So I changed,' showing that she yields to him. The final transformation is ambiguous: 'turned inside out', the phrasing here could signify that she undergoes a reversal in attitudes as the result of birthing a son, or that the experience of having the child 'burst' out is one that decimates her sense of self. The use of the definite article 'the' before 'child' rather than the possessive 'my' implies that she distances herself from her offspring. Nevertheless this last transition is clearly a permanent one; Thetis has been curtailed by the role of motherhood but whether she has been transformed by maternal love or merely beaten by the pain of childbirth.

Structure

Each stanza is a sestet but the line lengths vary significantly, giving the appearance of irregularity; perhaps Duffy is implying that while things change shape, underneath, everything remains the same. The rhythm of the poem is irregular; there is frequent use of run-on lines (a zebra's gore /in my lower jaw) but also unexpected caesuras ('Size 8. Snake.') reflecting the frantic movement of Thetis as she moves quickly from one form to another, sometimes changing tack.