<PAGE>

                                                                   EXHIBIT 10.24


THIS WARRANT AND THE SHARES ISSUABLE HEREUNDER HAVE NOT BEEN REGISTERED UNDER
THE SECURITIES ACT OF 1933, AS AMENDED, AND MAY NOT BE SOLD PLEDGED, OR
OTHERWISE TRANSFERRED WITHOUT AN EFFECTIVE REGISTRATION THEREOF UNDER SUCH ACT
OR PURSUANT TO RULE 144 OR AN OPINION OF COUNSEL REASONABLY SATISFACTORY TO THE
CORPORATION AND ITS COUNSEL, THAT SUCH REGISTRATION IS NOT REQUIRED.

                     ____________________________________

                          WARRANT TO PURCHASE STOCK

Warrant to Purchase 180,000         Issue Date:              January 31, 2000
Shares of the Series E Preferred    Expiration Date:         January 31, 2005
Stock of PETOPIA.COM, INC.          Initial Exercise Price:  $5.6061 per share

THIS WARRANT CERTIFIES THAT, for the agreed upon value of $1.00 and for other
good and valuable consideration, GREYROCK CAPITAL, A DIVISION OF BANC OF AMERICA
COMMERCIAL FINANCE CORPORATION ("Holder") is entitled to purchase the number of
fully paid and non-assessable shares of the class of securities (the "Shares")
of the corporation (the "Company") at the initial exercise price per Share (the
"Warrant Price") all as set forth above and as adjusted pursuant to Article 2 of
this Warrant, subject to the provisions and upon the terms and conditions set
forth in this Warrant.

ARTICLE 1. EXERCISE.

  1.1  Method of Exercise. Holder may exercise this Warrant by delivering a duly
executed Notice of Exercise in substantially the form attached as Appendix 1 to
the principal office of the Company at any time prior to the earlier of (i)
January 31, 2005, or (ii) the date that is three (3) years after the closing of
the Company's initial public offering of common stock pursuant to a registration
statement on Form S-1 (or successor form). Unless Holder is exercising the
conversion right set forth in Section 1.2, Holder shall also deliver to the
Company a check for the aggregate Warrant Price for the Shares being purchased.

  1.2  Conversion Right. In lieu of exercising this Warrant as specified in
Section 1.1, Holder may from time to time convert this Warrant, in whole or in
part, into a number of Shares determined by dividing (a) the aggregate Fair
Market Value of the Shares or other securities otherwise issuable upon exercise
of this Warrant minus the aggregate Warrant Price of such Shares by (b) the Fair
Market Value of one Share. The Fair Market Value of the Shares shall be
determined pursuant Section 1.4.

   1.3 [Intentionally Deleted]

   1.4 Fair Market Value. The current "Fair Market Value" of the Shares or other
securities otherwise issuable upon exercise of this Warrant (collectively for
the purposes of this Section 1.4, the "Securities") on any date shall be:

  (a) If the securities are not registered under the Securities Exchange Act of
1934, as amended (the "Exchange Act"), the Fair Market Value of the Securities
shall be determined by the Board of Directors of the Company in its reasonable
good faith judgment. The foregoing notwithstanding, if Holder advises the Board
of Directors in writing that Holder disagrees with such determination, then the
Company and Holder shall promptly agree upon a reputable independent appraiser
experienced in valuing securities. In the event that the Company and the Holder
are unable to agree upon an independent appraiser within ten (10) business days
of the date on which a proposed candidate for independent appraiser is first
submitted by the Company or the Holder, then at the written request of either
the Company or the Holder, the President of the American Arbitration Association
shall designate the independent appraiser. The determination of such appraiser
shall be final and binding upon the parties, and the Company and the Holder
shall share equally the fees and expenses of such appraiser;
<PAGE>

Greyrock Capital                                       Warrant to Purchase Stock
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  (b) if the Securities are registered under the Exchange Act (i) if
such Securities are listed or admitted to trading on any securities exchange,
the closing price, regular way, on such day on the principal exchange on which
such Securities are traded, (ii) if such Securities are not then listed or
admitted to trading on any securities exchange, the last reported sale price on
such day, or (iii) if  neither clause (i) or (ii) is applicable, the average of
the reported high bid and low asked prices on such day, as reported by a
reputable quotation service designated by the Company.

  1.5 Delivery of Certificate and New Warrant. Promptly after Holder exercises
or converts this Warrant, the Company shall deliver to Holder certificates for
the Shares acquired and, if this Warrant has not been fully exercised or
converted and has not expired, a new Warrant representing the Shares not so
acquired.

  1.6 Replacement of Warrants. On receipt of evidence reasonably satisfactory to
the Company of the loss, theft, destruction or mutilation of this Warrant and,
in the case of loss, theft or destruction, on delivery of an indemnity agreement
reasonably satisfactory in form and amount to the Company or, in the case of
mutilation, on surrender and cancellation of this Warrant, the Company at its
expense shall execute and deliver, in lieu of this Warrant, a new warrant of
like tenor.

  1.7 Repurchase on Sale, Merger or Consolidation of the Company.

  1.7.1. "Acquisition". For the purpose of this Warrant, "Acquisition" means any
sale, license, or other disposition of all or substantially all of the assets of
the Company, or any reorganization, consolidation, or merger of the Company
where the holders of the Company's securities before the transaction
beneficially own less than 50% of the outstanding voting securities of the
surviving entity after the transaction.

  1.7.2. Assumption of Warrant. If upon the closing of any Acquisition the
successor entity assumes the obligations of this Warrant, then this Warrant
shall be exercisable for the same securities, cash, and property as would be
payable for the Shares issuable upon exercise of the unexercised portion of this
Warrant as if such Shares were outstanding on the record date for the
Acquisition and subsequent closing. The Warrant Price shall be adjusted
accordingly.

  1.7.3. Nonassumption. If upon the closing of any Acquisition the successor
entity does not assume the obligations of this Warrant and Holder has not
otherwise exercised this Warrant in full, then the unexercised portion of this
Warrant shall be deemed to have been automatically converted pursuant to Section
1.2 and thereafter Holder shall participate in the acquisition on the same terms
as other holders of the same class of securities of the Company.

ARTICLE 2.  ADJUSTMENTS TO THE SHARES.

  2.1 Stock Dividends, Splits, Etc. If the Company declares or pays a dividend
on its common stock (or the Shares if the Shares are securities other than
common stock) payable in common stock, or other securities, subdivides the
outstanding common stock into a greater amount of common stock, or, if the
Shares are securities other than common stock, subdivides the Shares in a
transaction that increases the amount of common stock into which the Shares are
convertible, then upon exercise of this Warrant, for each Share acquired, Holder
shall receive, without cost to Holder, the total number and kind of securities
to which Holder would have been entitled had Holder owned the Shares of record
as of the date the dividend or subdivision occurred.

  2.2 Reclassification, Exchange or Substitution. Upon any reclassification,
exchange, substitution, or other event that results in a change of the number
and/or class of the securities issuable upon exercise or conversion of this
Warrant, Holder shall be entitled to receive, upon exercise or conversion of
this Warrant, the number and kind of securities and property that Holder would
have received for the Shares if this Warrant had been exercised immediately
before such reclassification, exchange, substitution, or other event. Such an
event shall include any automatic conversion of the outstanding or issuable
securities of the Company of the same class or series as the Shares to common
stock pursuant to the terms of the Company's Articles of Incorporation upon the
closing of a registered public offering of the Company's common stock. The
Company or its successor shall promptly issue to

                                      -2-
<PAGE>

Greyrock Capital                                       Warrant to Purchase Stock
--------------------------------------------------------------------------------

Holder a new Warrant for such new securities or other property. The new Warrant
shall provide for adjustments which shall be as nearly equivalent as may be
practicable to the adjustments provided for in this Article 2 including, without
limitation, adjustments to the Warrant Price and to the number of securities or
property issuable upon exercise of the new Warrant. The provisions of this
Section 2.2 shall similarly apply to successive reclassifications, exchanges,
substitutions, or other events.

  2.3 Adjustments For Combinations, Etc. If the outstanding Shares are combined
or consolidated, by reclassification or otherwise, into a lesser number of
shares, the Warrant Price shall be proportionately increased.

  2.4 Adjustments for Diluting Issuances. The number of shares of common stock
issuable upon conversion of the Shares, shall be subject to adjustment, from
time to time in the manner set forth in the Company's Certificate of
Incorporation, as amended and restated.

  2.5 No Impairment. The Company shall not, by amendment of its Articles of
Incorporation or through a reorganization, transfer of assets, consolidation,
merger, dissolution, issue, or sale of securities or any other voluntary action,
avoid or seek to avoid the observance or performance of any of the terms to be
observed or performed under this Warrant by the Company, but shall at all times
in good faith assist in carrying out of all the provisions of this Article 2 and
in taking all such action as may be necessary or appropriate to protect Holder's
rights under this Article against impairment. If the Company takes any action
affecting the Shares or its common stock other than as described above that
adversely affects Holder's rights under this Warrant, the Warrant Price shall be
adjusted downward and the number of Shares issuable upon exercise of this
Warrant shall be adjusted upward in such a manner that the aggregate Warrant
Price of this Warrant is unchanged.

  2.6 Fractional Shares. No fractional Shares shall be issuable upon exercise or
conversion of the Warrant and the number of Shares to be issued shall be rounded
down to the nearest whole Share. If a fractional share interest arises upon any
exercise or conversion of the Warrant, the Company shall eliminate such
fractional share interest by paying Holder amount computed by multiplying the
fractional interest by the fair market value of a full Share.

  2.7 Certificate as to Adjustments. Upon each adjustment of the Warrant Price,
the Company at its expense shall promptly compute such adjustment, and furnish
Holder with a certificate of its Chief Financial Officer setting forth such
adjustment and the facts upon which such adjustment is based. The Company shall,
upon written request, furnish Holder a certificate setting forth the Warrant
Price in effect upon the date thereof and the series of adjustments leading to
such Warrant Price.

ARTICLE 3. REPRESENTATIONS AND COVENANTS OF THE COMPANY.

  3.1 Representations, Warranties and Covenants. The Company hereby represents,
warrants and covenants to the Holder as follows:

  (a) The initial Warrant Price referenced on the first page of this Warrant is
not greater than (i) the price per share at which the Shares were last issued in
an arms length transaction in which at least $500,000 of the Shares were sold
and (ii) the fair market value of the Shares as of the date of this Warrant.

  (b) The Company will reserve from its authorized and unissued Series E
Preferred Stock a sufficient number of shares to provide for the issuance of
Series E Preferred Stock upon the exercise of this Warrant (and shares of its
common stock for issuance on conversion of such Series E Preferred Stock) and,
from time to time, will take all steps necessary to amend its Certificate of
Incorporation to provide sufficient reserves of shares of Series E Preferred
Stock issuable upon exercise of this Warrant (and shares of its common stock for
issuance on conversion of such Series E Preferred Stock). All Shares which may
be issued upon the exercise of the purchase right represented by this Warrant,
and all securities, if any, issuable upon conversion of the Shares, shall, upon
issuance, be duly authorized, validly issued, fully paid and non-assessable, and
free of any liens and encumbrances except for restrictions on transfer provided
for herein or under applicable federal and state securities laws.

                                      -3-
<PAGE>

Greyrock Capital                                       Warrant to Purchase Stock
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  (c) The capitalization of the Company at January 31, 2000, is as follows:

      (i)  Common Stock. 71,180,000 shares of Common Stock (the "Common Stock"),
           -------------
9,873,718 of which are issued and outstanding, 585,000 of which have been
reserved for issuance upon the exercise of warrants to purchase Common Stock
issued or issuable to the founders of Loveland Pet Products, Inc. (the "Loveland
Warrants") and 917,749 of which have been reserved for issuance upon the
exercise of warrants to purchase Common Stock issued to National Broadcasting
Company, Inc. (the "NBC Warrants"). The Company has reserved (A) 11,555,000
shares of Common Stock for issuance upon conversion of the Series A Preferred
Stock; (B) 8,000,000 shares of Common Stock for issuance upon conversion of the
Series B Preferred Stock; (C) 12,940,620 shares of Common Stock for issuance
upon conversion of the Series C Preferred Stock; (D) 14,000,000 shares of Common
Stock for issuance upon conversion of the Series D Preferred Stock; and (E)
2,330,000 shares of Common Stock for issuance upon conversion of the Series E
Preferred Stock.

      (ii) Preferred Stock. 49,180,000 shares of Preferred Stock (the "Preferred
           ----------------
Stock"): (A) 11,555,000 of which have been designated Series A Preferred Stock,
9,755,000 of which are issued and outstanding and 1,800,000 of which have been
reserved for issuance upon exercise of warrants to purchase Series A Preferred
Stock (the "Series A Warrants"); (B) 8,000,000 of which have been designated
Series B Preferred Stock, 7,736,345 of which are issued and outstanding; (C)
12,940,620 of which have been designated Series C Preferred Stock, 3,017,175 of
which are issued and outstanding, 4,803,458 of which have been reserved for
issuance to PETCO Animal Supplies, Inc. ("PETCO") upon the achievement of
certain milestones (the "PETCO Shares") and 5,119,987 of which have been
reserved for issuance upon exercise of warrants to purchase shares of Series C
Preferred Stock (the "Series C Warrants"); (D) 14,000,000 shares of which have
been designated Series D Preferred Stock, 9,837,804 of which are issued and
outstanding and 918,948 of which have been reserved for issuance upon exercise
of warrants to purchase shares of Series D Preferred Stock (the "Series D
Warrants"); and (E) 2,330,000 shares of which have been designated Series E
Preferred Stock, 2,007,637 of which are issued and outstanding, 76,617 of which
have been reserved for issuance upon exercise of warrants to purchase shares of
Series E Preferred Stock (the "ICOD Warrants") and 180,000 of which have been
reserved for issuance upon exercise of this Warrant (together with the ICOD
Warrants, the "Series E Warrants").

      (iii) 1999 Stock Plan. The Company has reserved 7,500,000 shares of Common
            ----------------
Stock for issuance to officers, directors, employees and consultants of the
Company pursuant to its 1999 Stock Plan duly adopted by the Board of Directors
and approved by the Company's stockholders (the "Stock Plan"), of which options
to purchase 5,016,769 shares of Common Stock are currently outstanding,
2,024,157 shares of Common Stock are issued and outstanding and 459,074 shares
are available for future issuance under the Stock Plan.

  3.2 Notice Of Certain Events. If the Company proposes at any time (a) to
declare any dividend or distribution upon its common stock, whether in cash,
property, stock, or other securities and whether or not a regular cash dividend;
(b) to offer for subscription pro rata to the holders of Series E Preferred
Stock any additional shares of stock of any class or series or other rights; (c)
to effect any reclassification or recapitalization of common stock; or (d) to
merge or consolidate with or into any other corporation, or sell, lease,
license, or convey all or substantially all of its assets, or to liquidate,
dissolve or wind up then, in connection with each such event, the Company shall
give Holder (1) at least 15 days prior written notice of the date on which a
record will be taken for such dividend, distribution, or subscription rights
(and specifying the date on which the holders of common stock will be entitled
thereto) or for determining rights to vote, if any, in respect of the matters
referred to in (c) and (d) above; and (2) in the case of the matters referred to
in (c) and (d) above at least 15 days prior written notice of the date when the
same will take place (and specifying the date on which the holders of common
stock will be entitled to exchange their common stock for securities or other
property deliverable upon the occurrence of such event).

  3.4 Registration Under Securities Act of 1933, As Amended. The Company agrees
that the Shares shall be included within the definition of "Registrable
Securities" under the Company's Fourth Amended and Restated Investors' Rights
Agreement attached hereto as Exhibit A.

ARTICLE 4. MISCELLANEOUS.
           -------------

                                      -4-
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Greyrock Capital                                       Warrant to Purchase Stock
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  4.1 Term. This Warrant is exercisable, in whole or in part, at any time and
from time to time on or before the earlier of (i) January 31, 2005, or (ii) the
date that is three (3) years after the closing of the Company's initial public
offering of common stock pursuant to a registration statement on Form S-1 (or
successor form).

  4.2 Legends. This Warrant and the Shares (and the securities issuable,
directly or indirectly, upon conversion of the Shares, if any) shall be
imprinted with a legend in substantially the following form:

  THIS SECURITY HAS NOT BEEN REGISTERED UNDER THE SECURITIES ACT OF 1933, AS
AMENDED, AND MAY NOT BE SOLD, PLEDGED OR OTHERWISE TRANSFERRED WITHOUT AN
EFFECTIVE REGISTRATION THEREOF UNDER SUCH ACT OR PURSUANT TO RULE 144 OR AN
OPINION OF COUNSEL REASONABLY SATISFACTORY TO THE CORPORATION AND ITS COUNSEL
THAT SUCH REGISTRATION IS NOT REQUIRED.

  4.3 Compliance with Securities Laws on Transfer. This Warrant and the Shares
issuable upon exercise of this Warrant (and the securities issuable, directly or
indirectly, upon conversion of the Shares, if any) may not be transferred or
assigned in whole or in part without compliance with applicable federal and
state securities laws by the transferor and the transferee (including, without
limitation, the delivery of investment representation letters and legal opinions
reasonably satisfactory to the Company, if reasonably requested by the Company).

  4.4 Transfer Procedure. Subject to the provisions of Section 4.2 and 4.3,
Holder may transfer all or part of this Warrant or the Shares issuable upon
exercise of this Warrant (or the securities issuable, directly or indirectly,
upon conversion of the Shares, if any) by giving the Company notice of the
portion of the Warrant being transferred setting forth the name, address and
taxpayer identification number of the transferee and surrendering this Warrant
to the Company for reissuance to the transferee(s) (and Holder if applicable).
The Company shall have the right to refuse to transfer any portion of this
Warrant and the Shares issuable upon exercise of this Warrant (including
securities issuable, directly or indirectly, upon conversion of the Shares) to
any person who directly competes with the Company provided, however, that
                                                  --------  -------
nothing in the foregoing sentence shall prevent Holder from transferring shares
of the Company's securities after the Company's initial public offering.

  4.5 Notices. All notices and other communications from the Company to the
Holder, or vice versa, shall be deemed delivered and effective when given
personally or mailed by first-class registered or certified mail, postage
prepaid, at such address as may have been furnished to the Company or the
Holder, as the case may be, in writing by the Company or such holder from time
to time.

  4.6 Waiver. This Warrant and any term hereof may be changed, waived,
discharged or terminated only by an instrument in writing signed by the party
against which enforcement of such change, waiver, discharge or termination is
sought.

  4.7 Attorneys Fees. In the event of any dispute between the parties concerning
the terms and provisions of this Warrant, the party prevailing in such dispute
shall be entitled to collect from the other party all costs incurred in such
dispute, including reasonable attorneys' fees.

  4.8 Governing Law. This Warrant shall be governed by and construed in
accordance with the laws of the State of California, without giving effect to
its principles regarding conflicts of law.

PETOPIA.COM, INC.

By /s/
   --------------------------------------------------
   Chairman of the Board, President or Vice President

By
   __________________________________________________
   Secretary or Ass't Secretary

                                      -5-