creature
Heiðrún
The goat that stands by Valhalla and browses the tree Læraðr; from her udders flows mead enough to make all the einherjar drunk every day.
Heiðrún is the goat that supplies Valhalla with mead. Grímnismál says she stands by "Heerfather's hall", bites the branches of the tree Læraðr, and fills the pitcher with clear mead: "Ne'er fails the foaming drink" Grímnismál 25. The next stanza puts the hart Eikþyrnir beside her, eating from the same tree Grímnismál 26.
Snorri expands this in answer to a joke. Gangleri asks whether the warriors drink water, and Hárr retorts that Allfather would hardly invite kings and earls to drink water. Instead, Heiðrún "stands up in Valhall", which most read as standing on its roof, and bites the needles of Læraðr. From her udders comes so much mead that she fills a vat every day, enough to make all the einherjar drunk Gylfaginning 39. Snorri gives the mead an udder for a source; the poem mentions no udder.
Heiðrún appears once more, as an insult. At the end of Hyndluljóð, the giantess Hyndla tells Freyja: "out in the night thou leapest / As Heithrun goes the goats among" Hyndluljóð 47, accusing her of promiscuity Hyndluljóð 48. The comparison suggests that Heiðrún had a reputation of her own, but no story behind it survives.
Læraðr itself is named only in these two stanzas and in Snorri. Many readers identify it with Yggdrasil, but no source says so.
In the sources
Quoted from the hosted translations; each line is checked against the text when the site is built. Select a reference to read it in context.
Heithrun is the goat who stands by Heerfather's hall, And the branches of Lærath she bites; The pitcher she fills with the fair, clear mead, Ne'er fails the foaming drink.
The she-goat, she who is called Heidrún, stands up in Valhall and bites the needles from the limb of that tree which is very famous, and is called Lærádr; and from her udders mead runs so copiously, that she fills a tun every day.
My noble one, out in the night thou leapest As Heithrun goes the goats among.