Early-Pleistocene Homo erectus probably lived mostly at Indian Ocean shores.. Stone use = hard tools for opening fruits, shells etc., cf. sea-otters. There are at least 8 different (mutually independent) indications, some stronger than others, that H.erectus frequently collected shellfish:
--1) The atypical tooth wear in archaic Homo was caused by "sand & oral processing of marine mollusks" (Towle cs 2022 doi 10.1002/ajpa.24500).
--2) H.erectus fossilized amid shellfish & barnacles, e.g. Mojokerto.
--3) Stephen Munro found sea-shell engravings made by H.erectus (Joordens cs 2015 Nature 518:228–231).
--4) Ear exostoses (H.erectus & H.neand.) develop after years of cold(er) water irrigation.
--5) Pachy-osteo-sclerosis (very thick & dense cortical bone, erectus>neand..>sapiens) is typically & exclusively seen in slow+shallow-diving tetrapods (de Buffrénil cs 2010 J.Mamm.Evol.17:101–120), e.g. H.erectus parietal bone is twice as thick as in gorillas.
--6) Drastic brain enlargement, as in dolphins & pinnipeds, is facilitated by sea-food, e.g. docosahexaenoic acid DHA in shellfish.
--7) Homo’s stone tool use & manual dexterity is typical for molluscivores such as sea-otters.
--8) Pleistocene Homo even colonized overseas islands (Flores & later even Luzon), google “coastal dispersal Pleistocene Homo”.

Early humans certainly did NOT survive by chasing savanna antelopes! :-DDD The savanna idea of human evolution (e.g. “endurance running”) is the most unscientific fantasy thinkable, e.g. sweat = water + salt = both are scarce in savannas.
Google
- gondwanatalks verhaegen
- pachyosteosclerosis