This is a pictograph of a mugger crocodile nest. Therefore, it is the noun mugger crocodile nest.
Illustrative Text Reference:
Mohenjo-daro: Seal: The Schoyen Collection: Schoyen Reference: MS 5059 (A note on the Schoyen website says that this seal inscription wil be published in Volume 3 of the Corpus of Indus Seals and
Inscriptions.): https://www.schoyencollection.com/palaeography-collection-introduction/early-writing-introduction/4-1-4-indus-valley/indus-valley-seal-ms-5059: Accessed: 25 February 2018.
This is Mahadevan's sign number 1319, which I have redrawn to better represent the original.
The female mugger crocodile digs a hole in which to lay her eggs.